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Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
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#1
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Fibreglassing 101?
I need to make a couple of horns ( for audio use ) and have a couple of
questions as I never worked with this stuff before... The local Home Depot clone ( in scandinavia ) sells the glass fibres, polyester resin, hardener and gelcoat wich should be everything I need ? The mold is made from a big chunk of MDF ( Medium Density Fibreboard ) that I laminated from several smaller sheets, then cut the horn flare contour in it on a lathe.. To give you an idea of what I am trying to do I put a picture of an existing horn he http://www.naeslund.dk/peter/files/oprydning/hpt42.jpg The mold I made fits inside the horn.. Note that the actual horn I am trying to make is round, not rectangular like this.. Can anyone give me some idiot proof instructions on where to go from here, before I waste 100$ worth of fibreglassing ingredients? If not, heres a few questions: How do I get the surface thats touching the mold as smooth as possible? ( The mold was turned on a lathe, so it is smooth, but I'd prefer the fancy shiny surface :-) How do I keep the fibreglass from sticking to the mold? Any tips that may come in handy? I know that this process involves nasty chemicals and nasty dust, so I will be doing this outside wearing some sort of dust filtering mask.. Thanks in advance /peter |
#2
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On Sun, 17 Jul 2005 00:44:34 +0200, "Q" wrote:
I need to make a couple of horns ( for audio use ) and have a couple of questions as I never worked with this stuff before... The local Home Depot clone ( in scandinavia ) sells the glass fibres, polyester resin, hardener and gelcoat wich should be everything I need ? The mold is made from a big chunk of MDF ( Medium Density Fibreboard ) that I laminated from several smaller sheets, then cut the horn flare contour in it on a lathe.. To give you an idea of what I am trying to do I put a picture of an existing horn he http://www.naeslund.dk/peter/files/oprydning/hpt42.jpg The mold I made fits inside the horn.. Note that the actual horn I am trying to make is round, not rectangular like this.. Can anyone give me some idiot proof instructions on where to go from here, before I waste 100$ worth of fibreglassing ingredients? If not, heres a few questions: How do I get the surface thats touching the mold as smooth as possible? ( The mold was turned on a lathe, so it is smooth, but I'd prefer the fancy shiny surface :-) That surface needs to be as non-porous as possible. Seal it with whatever your fiberglass supplier has on hand and recommends. Furane is one product, sprays easily, dries fast, sands readily, polishes shiny, smells terrible. It's not very durable though. How do I keep the fibreglass from sticking to the mold? After sealing the surface, use a specialty type paste wax. Apply wax, let dry as recommended (perhaps overnight), and buff. Do about 6 coats. Do not try to speed the process. You might also bake the mold in a warm oven between coats to help get the wax to penetrate the surface. For at least the first part, apply a couple of coats of PVA (from the fiberglass supplier). Spray it on if you can, it won't brush very well on a waxed surface. Any tips that may come in handy? I can't tell you how many times I've heard that folks making their first piece don't get the mold sealed and waxed properly, and end up with the mold and the part permanently bonded together. So you might try sealing and waxing some samples first to test that your technique is adequate. The first release on a new mold can be troublesome. Try getting a little compressed air into one corner. If that doesn't work, try getting some water into the released areas to dissolve the PVA. After the first release, add another coat of wax. If the first part was tough to release, you might use PVA on the second one as well. But if the mold is properly prepped, all releases after the first one should be easy. The tail on your horn doesn't appear to have much taper, and the part is going to shrink around the mold. So expect the part to have a good grip on your mold in that area. You might make the first part a single layer thick. That will give you some layup practice, and enable you to peel the part off the mold if it's stuck in some areas. Wayne |
#3
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"Q" wrote in message ... I need to make a couple of horns ( for audio use ) and have a couple of questions as I never worked with this stuff before... The local Home Depot clone ( in scandinavia ) sells the glass fibres, polyester resin, hardener and gelcoat wich should be everything I need ? The mold is made from a big chunk of MDF ( Medium Density Fibreboard ) that I laminated from several smaller sheets, then cut the horn flare contour in it on a lathe.. To give you an idea of what I am trying to do I put a picture of an existing horn he http://www.naeslund.dk/peter/files/oprydning/hpt42.jpg The mold I made fits inside the horn.. Note that the actual horn I am trying to make is round, not rectangular like this.. Can anyone give me some idiot proof instructions on where to go from here, before I waste 100$ worth of fibreglassing ingredients? If not, heres a few questions: How do I get the surface thats touching the mold as smooth as possible? ( The mold was turned on a lathe, so it is smooth, but I'd prefer the fancy shiny surface :-) How do I keep the fibreglass from sticking to the mold? Any tips that may come in handy? I know that this process involves nasty chemicals and nasty dust, so I will be doing this outside wearing some sort of dust filtering mask.. Thanks in advance /peter 1.Mold release to prevent the part sticking to the mold, one brand name is Freekote, choose one that cures at room temp. 2. The gel coat goes on first, that's what makes the smooth surface. 3.Follow the directions for the resin system you have picked out, i.e. cure times for the gel coat before bond coats and fabric, shouldn't have any problems. 4. Do wear protective gear, you can build a reaction to the stuff over time, so no bare hands. 5. Good luck! |
#4
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Any local boat repair guys? Marinas? They'll show you just what you need.
"Q" wrote in message ... I need to make a couple of horns ( for audio use ) and have a couple of questions as I never worked with this stuff before... The local Home Depot clone ( in scandinavia ) sells the glass fibres, polyester resin, hardener and gelcoat wich should be everything I need ? The mold is made from a big chunk of MDF ( Medium Density Fibreboard ) that I laminated from several smaller sheets, then cut the horn flare contour in it on a lathe.. To give you an idea of what I am trying to do I put a picture of an existing horn he http://www.naeslund.dk/peter/files/oprydning/hpt42.jpg The mold I made fits inside the horn.. Note that the actual horn I am trying to make is round, not rectangular like this.. Can anyone give me some idiot proof instructions on where to go from here, before I waste 100$ worth of fibreglassing ingredients? If not, heres a few questions: How do I get the surface thats touching the mold as smooth as possible? ( The mold was turned on a lathe, so it is smooth, but I'd prefer the fancy shiny surface :-) How do I keep the fibreglass from sticking to the mold? Any tips that may come in handy? I know that this process involves nasty chemicals and nasty dust, so I will be doing this outside wearing some sort of dust filtering mask.. Thanks in advance /peter |
#5
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"wmbjk" skrev i en meddelelse ... That surface needs to be as non-porous as possible. Seal it with whatever your fiberglass supplier has on hand and recommends. Furane is one product, sprays easily, dries fast, sands readily, polishes shiny, smells terrible. It's not very durable though. The supplier is a local Home Depot clone w. highschool student employees, so I doubt they have any recommandations :-)... They do have a boating supply dept, wich is where I found the fibreglass stuff.. I found some silicon based mold release designed for Polyester resins at an electronics supply place.. I just ordered a couple of cans.. How do I keep the fibreglass from sticking to the mold? After sealing the surface, use a specialty type paste wax. Apply wax, let dry as recommended (perhaps overnight), and buff. Do about 6 coats. Do not try to speed the process. You might also bake the mold in a warm oven between coats to help get the wax to penetrate the surface. For at least the first part, apply a couple of coats of PVA (from the fiberglass supplier). Spray it on if you can, it won't brush very well on a waxed surface. Any clue if boatwax will work? PVA is regular (white) wood glue ?... I could add a little destilled water and spray it on Someone mentioned using babypowder on the mold as a release.. Will that work? Any tips that may come in handy? I can't tell you how many times I've heard that folks making their first piece don't get the mold sealed and waxed properly, and end up with the mold and the part permanently bonded together. So you might try sealing and waxing some samples first to test that your technique is adequate. The first release on a new mold can be troublesome. Try getting a little compressed air into one corner. If that doesn't work, try getting some water into the released areas to dissolve the PVA. After the first release, add another coat of wax. If the first part was tough to release, you might use PVA on the second one as well. But if the mold is properly prepped, all releases after the first one should be easy. The tail on your horn doesn't appear to have much taper, and the part is going to shrink around the mold. So expect the part to have a good grip on your mold in that area. You might make the first part a single layer thick. That will give you some layup practice, and enable you to peel the part off the mold if it's stuck in some areas. I could integrate a quickrelease fitting for the airhose in the mold, so I can blow air between the mold and the piece.. I could do just a few layers on the mold, let it harden and add more layers after I remove it from the mold... This would help the shrinking problem to some degree, or am I way off track ? Thanks for the input so far! /peter |
#6
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"Franklin Newton" skrev i en meddelelse ink.net... 1.Mold release to prevent the part sticking to the mold, one brand name is Freekote, choose one that cures at room temp. I found some silicon based stuff.... If I start by applying a layer of polyester on the mold, let it harden and spray it with the silicon based stuff, will this be enough? 2. The gel coat goes on first, that's what makes the smooth surface. AHA!... I learned something new today :-) 3.Follow the directions for the resin system you have picked out, i.e. cure times for the gel coat before bond coats and fabric, shouldn't have any problems. The directions are on the cans, so that wont be a problem.. 4. Do wear protective gear, you can build a reaction to the stuff over time, so no bare hands. Yup... have heard about some poor aircraft maintenance person who sprayed his arm w. resin by accident.. The story says that the arm more or less rotted in a few weeks... Besides local OSHA codes on the fibreglass industry are mad here...I think you'd need less protective equipment to walk on the moon :-) 5. Good luck! Thanks, and thanks for the input.. /peter |
#7
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"Eide" skrev i en meddelelse news:yyhCe.64565$R21.12623@lakeread06... Any local boat repair guys? Marinas? They'll show you just what you need. I have been looking around the area to see if I could bribe someone to do these horns for me, but no luck so far.. Besides.. I might aswell play a little with nasty chemicals :-) /peter |
#8
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Q writes:
How do I keep the fibreglass from sticking to the mold? Silicone grease spread thinly, or petrolatum (Vaseline), or Rain-X. This isn't that difficult. You don't fancy mold-release products. You can also craft your mold out of that cheap pink polyester Bondo. Unlike the MDF, you can add it as well as take it away. |
#9
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It's not that toxic, the Portuguese guys around here (RI) had been spreading
it with their bare hands until a few years ago. Don't get me wrong, most of them aren't around anymore, and those that are have the shakes, but you won't be rotting your arms off. Yup... have heard about some poor aircraft maintenance person who sprayed his arm w. resin by accident.. The story says that the arm more or less rotted in a few weeks... Besides local OSHA codes on the fibreglass industry are mad here...I think you'd need less protective equipment to walk on the moon :-) |
#10
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I have been making one off patterns molds and parts regularly for the boat
and can tell you what works for me but I don't know what would be available where you are. Scandinavia is a big place. I think Denmark and Sweden have some good sources for composite materials. Mold finish: I sand to about 120 and spray on a polyester based tooling primer called Duratec Surface primer. It is a soft high build polyester primer. Wet sand from 400 to 1200 then an automotive compound and finally a fine polish like McGuire's. Two coats of cake type carnauba based automotive wax as a base for the mold release. Mold release: PVA is polyvinyl alcohol. A green liquid that dries to a thin water soluble film. Spray a very light coat as a binder coat. After about 10 minutes it will be dry enough to spray a wet coat. Glassing: To do a proper job you need several different glass fabrics and the Home Despot is definitely not toe place to get them. Price is way to high and you will be lucky to find anything outer than 6 oz plain weave cloth. Some terminology: "Gel Coat" is a thick surfacing polyester with lots of solids. It is the surface that you see when you look at most fiberglass boats. "Cloth" is a plain weave material. It comes in various weights from ..5 oz/sq yard to 8 oz. and is used to reinforce the surface. "Roving" is a very heavy yarn woven into a loose fabric. It is used for strength and mass. "Mat" is a random oriented fiberglass felt like material used to fill the voids in the coarser roving and prevent the weave pattern from printing through the gel coat. "Sanding Aid" is a liquid wax additive that is mixed with the last coat of polyester resin. Polyester does not cure hard in the presence of air. The wax migrates to the surface and forms a shielding layer to keep air away from the curing resin. Start with a sprayed on polyester gel coat as soon as the first coat has flashed off spray on another. You can roll it on but be careful not to damage the PVA release. Repeat until you have about 30 mills of thickness and let is cure for an hour or so. Then you can roll on some regular polyester resin and lay a scrim of 2oz cloth followed by a layer of 6 oz cloth and a layer of 8oz mat. You want the resin to fully wet out everything. Next come several layers alternating roving and mat to build the thickness you need. Cover the last layer of mat with some 6 oz cloth and seal it with resin with the wax additive.. -- Glenn Ashmore I'm building a 45' cutter in strip/composite. Watch my progress (or lack there of) at: http://www.rutuonline.com Shameless Commercial Division: http://www.spade-anchor-us.com "Q" wrote in message ... I need to make a couple of horns ( for audio use ) and have a couple of questions as I never worked with this stuff before... The local Home Depot clone ( in scandinavia ) sells the glass fibres, polyester resin, hardener and gelcoat wich should be everything I need ? The mold is made from a big chunk of MDF ( Medium Density Fibreboard ) that I laminated from several smaller sheets, then cut the horn flare contour in it on a lathe.. To give you an idea of what I am trying to do I put a picture of an existing horn he http://www.naeslund.dk/peter/files/oprydning/hpt42.jpg The mold I made fits inside the horn.. Note that the actual horn I am trying to make is round, not rectangular like this.. Can anyone give me some idiot proof instructions on where to go from here, before I waste 100$ worth of fibreglassing ingredients? If not, heres a few questions: How do I get the surface thats touching the mold as smooth as possible? ( The mold was turned on a lathe, so it is smooth, but I'd prefer the fancy shiny surface :-) How do I keep the fibreglass from sticking to the mold? Any tips that may come in handy? I know that this process involves nasty chemicals and nasty dust, so I will be doing this outside wearing some sort of dust filtering mask.. Thanks in advance /peter |
#11
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Q wrote:
PVA is regular (white) wood glue ? Yes, it is. But you should not take a water-resistant for obvious reasons. :-)) Nick -- Motormodelle / Engine Models: http://www.motor-manufaktur.de Ellwe 2FB * VTM 87 * DLM-S3a * cubic more to come ... |
#12
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"Glenn Ashmore" skrev i en meddelelse news:xOlCe.171881$sy6.140027@lakeread04... I have been making one off patterns molds and parts regularly for the boat and can tell you what works for me but I don't know what would be available where you are. Scandinavia is a big place. I think Denmark and Sweden have some good sources for composite materials. The main problem here seems to be limited availability simply because very few people do stuff like this at home.. From the sound of the replies I think I need to stop by one of the local yachtbuilders and see if they will sell me the materials I need.. The Home Depot clone only has one grade of cloth ( 300 grams per sq. meter ) and it aint cheap.... Altho: A common wallpaper type here is woven glass cloth is dirt cheap.. Could I use the Home Depot clone for the first layer ( the inner layer actually, but this is the layer that would be visible ) and just use the wallpapergrade stuff for a "filler" ? I dont need much strength, just need it to be relatively stiff... Mold finish: I sand to about 120 and spray on a polyester based tooling primer called Duratec Surface primer. It is a soft high build polyester primer. Wet sand from 400 to 1200 then an automotive compound and finally a fine polish like McGuire's. Two coats of cake type carnauba based automotive wax as a base for the mold release. Sounds reasonably simple... Although I'd need to replace the primer etc. for something local... Mold release: PVA is polyvinyl alcohol. A green liquid that dries to a thin water soluble film. Spray a very light coat as a binder coat. After about 10 minutes it will be dry enough to spray a wet coat. Seems I am going to the yachtbuilder again :-) Glassing: To do a proper job you need several different glass fabrics and the Home Despot is definitely not toe place to get them. Price is way to high and you will be lucky to find anything outer than 6 oz plain weave cloth. Seems I am going to the yachtbuilder again :-) Some terminology: "Gel Coat" is a thick surfacing polyester with lots of solids. It is the surface that you see when you look at most fiberglass boats. "Cloth" is a plain weave material. It comes in various weights from .5 oz/sq yard to 8 oz. and is used to reinforce the surface. "Roving" is a very heavy yarn woven into a loose fabric. It is used for strength and mass. "Mat" is a random oriented fiberglass felt like material used to fill the voids in the coarser roving and prevent the weave pattern from printing through the gel coat. "Sanding Aid" is a liquid wax additive that is mixed with the last coat of polyester resin. Polyester does not cure hard in the presence of air. The wax migrates to the surface and forms a shielding layer to keep air away from the curing resin. Excellent.. I needed some words here and there :-) Start with a sprayed on polyester gel coat as soon as the first coat has flashed off spray on another. You can roll it on but be careful not to damage the PVA release. Repeat until you have about 30 mills of thickness and let is cure for an hour or so. Then you can roll on some regular polyester resin and lay a scrim of 2oz cloth followed by a layer of 6 oz cloth and a layer of 8oz mat. You want the resin to fully wet out everything. Next come several layers alternating roving and mat to build the thickness you need. Cover the last layer of mat with some 6 oz cloth and seal it with resin with the wax additive.. This was exactly what I was looking for, now I just need to source the materials and try not to end up spending thousands of dollars in the process :-) /peter |
#13
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Q wrote:
The main problem here seems to be limited availability But you should have model builder shops (planes, ships) that sell that stuff. At least per mail order. Or you get hints where to look for at modelbuilders forums (yes, the colorful forums are evil for NewsGroups users). Nick -- Motormodelle / Engine Models: http://www.motor-manufaktur.de Ellwe 2FB * VTM 87 * DLM-S3a * cubic more to come ... |
#14
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"Nick Müller" skrev i en meddelelse ... Q wrote: PVA is regular (white) wood glue ? Yes, it is. But you should not take a water-resistant for obvious reasons. :-)) Know of any online shops in Germany that sell the fibreglass materials?... Am just north of you in Denmark, so it wouldnt be a huge problem getting the stuff from Germany? /peter |
#15
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"Nick Müller" skrev i en meddelelse ... Q wrote: The main problem here seems to be limited availability But you should have model builder shops (planes, ships) that sell that stuff. At least per mail order. Or you get hints where to look for at modelbuilders forums (yes, the colorful forums are evil for NewsGroups users). Most of the model builders I know either buy their stuff at the place I mentioned or from Conrad in Germany.. Problem is the quantity... I need more than a model boat would need but on the other hand I dont need a 55 gallon drum of polyester :-) I am going to Wacken near Hamburg in a few weeks ( www.wacken.com ) and could stop in Hamburg if there are any good places to get the materials I need? /peter |
#16
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Q wrote:
Know of any online shops in Germany that sell the fibreglass materials?... Yep! Here you go (even in English): http://www.r-g.de/ Don't know wether they ship to Denmark, but I guess. This company seems to be the best resource for that stuff. At least I've seen it referenced many times in model builders NGs. I'm not in the laminating. HTH, Niick -- Motormodelle / Engine Models: http://www.motor-manufaktur.de Ellwe 2FB * VTM 87 * DLM-S3a * cubic more to come ... |
#17
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Q wrote:
Conrad in Germany.. Urgs! Not the best place. For anything. :-) I am going to Wacken near Hamburg in a few weeks ( www.wacken.com ) and could stop in Hamburg if there are any good places to get the materials I need? I'm from Munich, so I can't help you now. But I will post in de.rec.modelle.misc to find a shop for you in Hamburg. Stay tuned ... Nick -- Motormodelle / Engine Models: http://www.motor-manufaktur.de Ellwe 2FB * VTM 87 * DLM-S3a * cubic more to come ... |
#18
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"Nick Müller" skrev i en meddelelse ... Q wrote: Know of any online shops in Germany that sell the fibreglass materials?... Yep! Here you go (even in English): http://www.r-g.de/ This looks perfect.. I dont know about the prices, but compared to bribing a yachtbuilder to do the hoens for me this would most likely be cheaper... Don't know wether they ship to Denmark, but I guess. This company seems to be the best resource for that stuff. At least I've seen it referenced many times in model builders NGs. I'm not in the laminating. It seems that they do ship to DK.. Now I am just confused about the quantities to order :-).. /peter |
#19
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I'd also check for any radio control model airplane clubs or experimental
aircraft groups in your area as they might have several individuals that are conversent on the composite subject. How bout kit car manufacturers? They use glass bodies quite a bit. One thing I'm impressed with is the willingness of the r.c.m guys to offer knowlegable suggestions on subjects far from metal. Sometimes I think that rec.crafts...should be "materials" instead of metal.. Regards Pat |
#20
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All the materials I mentioned are regularly used by all sorts of composite
workers. You should be able to find a distributor of FRP supplies somewhere around any major coastal city or you can search the web for mail order distributors Northern Europe. You might try Bang & Bonsomer in Finland or Armatech in Sweden. They are distributors but can tell you who sells their products retail. Or check with a local small boat designer for a source A quick Google came up with http://www.thomassondesign.com/index.php . FRP canoes use all the materials you will need. In order from worst place to best places to buy composite supplies in the quantity and types you need a 1) Model builder supply stores (Don't carry the heavier materials and they specialize in small quantities so the price will be WAY to high.) 2) Big Box building Supply stores ( very limited choice and high prices) 3) Commercial boat builders - ( have everything you need but no way to sell it to you. You have to rely on the sympathy factor) 4) Chandlers (boating supply store) (Usually can get anything you need but at a price) 5) Mail order boat building supply companies (Set up to sell cut length material and resins in liters) As a wild guess I would think that an Electrovoice HPT42 horn would require about 250 ml of gel coat, 2 meters of 2 and 6 oz cloth, 3-4 meters of mat and roving and a little more than a liter of polyester. If your low end is limited to 1300 Hz you can build it a lot lighter than a low end horn. If you are working on a low end horn double or triple the roving and mat. Either way be sure to roll out all the voids and consolidate the lay-up really well. Any voids are going to add unwanted color. Ideally I would vacuum bag the mat/roving lay-up. Keep the temperatures fairly low and cut back some on the MEK (catalyst) to extend your working time long enough to get the bag pulled before the resin kicks.. -- Glenn Ashmore I'm building a 45' cutter in strip/composite. Watch my progress (or lack there of) at: http://www.rutuonline.com Shameless Commercial Division: http://www.spade-anchor-us.com "Q" wrote in message ... "Glenn Ashmore" skrev i en meddelelse news:xOlCe.171881$sy6.140027@lakeread04... I have been making one off patterns molds and parts regularly for the boat and can tell you what works for me but I don't know what would be available where you are. Scandinavia is a big place. I think Denmark and Sweden have some good sources for composite materials. The main problem here seems to be limited availability simply because very few people do stuff like this at home.. From the sound of the replies I think I need to stop by one of the local yachtbuilders and see if they will sell me the materials I need.. The Home Depot clone only has one grade of cloth ( 300 grams per sq. meter ) and it aint cheap.... Altho: A common wallpaper type here is woven glass cloth is dirt cheap.. Could I use the Home Depot clone for the first layer ( the inner layer actually, but this is the layer that would be visible ) and just use the wallpapergrade stuff for a "filler" ? I dont need much strength, just need it to be relatively stiff... Mold finish: I sand to about 120 and spray on a polyester based tooling primer called Duratec Surface primer. It is a soft high build polyester primer. Wet sand from 400 to 1200 then an automotive compound and finally a fine polish like McGuire's. Two coats of cake type carnauba based automotive wax as a base for the mold release. Sounds reasonably simple... Although I'd need to replace the primer etc. for something local... Mold release: PVA is polyvinyl alcohol. A green liquid that dries to a thin water soluble film. Spray a very light coat as a binder coat. After about 10 minutes it will be dry enough to spray a wet coat. Seems I am going to the yachtbuilder again :-) Glassing: To do a proper job you need several different glass fabrics and the Home Despot is definitely not toe place to get them. Price is way to high and you will be lucky to find anything outer than 6 oz plain weave cloth. Seems I am going to the yachtbuilder again :-) Some terminology: "Gel Coat" is a thick surfacing polyester with lots of solids. It is the surface that you see when you look at most fiberglass boats. "Cloth" is a plain weave material. It comes in various weights from .5 oz/sq yard to 8 oz. and is used to reinforce the surface. "Roving" is a very heavy yarn woven into a loose fabric. It is used for strength and mass. "Mat" is a random oriented fiberglass felt like material used to fill the voids in the coarser roving and prevent the weave pattern from printing through the gel coat. "Sanding Aid" is a liquid wax additive that is mixed with the last coat of polyester resin. Polyester does not cure hard in the presence of air. The wax migrates to the surface and forms a shielding layer to keep air away from the curing resin. Excellent.. I needed some words here and there :-) Start with a sprayed on polyester gel coat as soon as the first coat has flashed off spray on another. You can roll it on but be careful not to damage the PVA release. Repeat until you have about 30 mills of thickness and let is cure for an hour or so. Then you can roll on some regular polyester resin and lay a scrim of 2oz cloth followed by a layer of 6 oz cloth and a layer of 8oz mat. You want the resin to fully wet out everything. Next come several layers alternating roving and mat to build the thickness you need. Cover the last layer of mat with some 6 oz cloth and seal it with resin with the wax additive.. This was exactly what I was looking for, now I just need to source the materials and try not to end up spending thousands of dollars in the process :-) /peter |
#21
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Q wrote:
This looks perfect.. I dont know about the prices, It just came to my mind, that R&G is filling the bottles for Conrad (there's a fine print on Conrad's bottles). So you can guess who has the better prices... Now I am just confused about the quantities to order :-).. Don't know. But there should be a rule of thump. Maybe 20% resin compared to the fibre? You don't want to much resin, it just has to glue the fibres together, 'cause the resin is weak compared to the fibres. Some illuminated here will have a better answer. I'm still waiting for tips for other suppliers (maybe in Hamburg) Nick -- Motormodelle / Engine Models: http://www.motor-manufaktur.de Ellwe 2FB * VTM 87 * DLM-S3a * cubic more to come ... |
#22
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Just checked out the R&G site. Looks like they have everything you need
except the tooling primer. Prices seem a little high but not outrageous. That VAT really kills you guys. Check out my post further down the thread for a SWAG on quantities. Always best to order a bit extra. You can always find a use for it later. -- Glenn Ashmore I'm building a 45' cutter in strip/composite. Watch my progress (or lack there of) at: http://www.rutuonline.com Shameless Commercial Division: http://www.spade-anchor-us.com "Q" wrote in message ... "Nick Müller" skrev i en meddelelse ... Q wrote: Know of any online shops in Germany that sell the fibreglass materials?... Yep! Here you go (even in English): http://www.r-g.de/ This looks perfect.. I dont know about the prices, but compared to bribing a yachtbuilder to do the hoens for me this would most likely be cheaper... Don't know wether they ship to Denmark, but I guess. This company seems to be the best resource for that stuff. At least I've seen it referenced many times in model builders NGs. I'm not in the laminating. It seems that they do ship to DK.. Now I am just confused about the quantities to order :-).. /peter |
#23
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"Glenn Ashmore" skrev i en meddelelse news:5DsCe.171890$sy6.143080@lakeread04... All the materials I mentioned are regularly used by all sorts of composite workers. You should be able to find a distributor of FRP supplies somewhere around any major coastal city or you can search the web for mail order distributors Northern Europe. You might try Bang & Bonsomer in Finland or Armatech in Sweden. They are distributors but can tell you who sells their products retail. Or check with a local small boat designer for a source A quick Google came up with http://www.thomassondesign.com/index.php . FRP canoes use all the materials you will need. Nick Müller pointed me towards www.r-g-composites.com and they seem to be willing to ship to Denmark, although the resin seems to be cheaper at the local home depot wannabe.... As a wild guess I would think that an Electrovoice HPT42 horn would require about 250 ml of gel coat, 2 meters of 2 and 6 oz cloth, 3-4 meters of mat and roving and a little more than a liter of polyester. If your low end is limited to 1300 Hz you can build it a lot lighter than a low end horn. If you are working on a low end horn double or triple the roving and mat. These are approx. 4 times the size... So if I order: 10 lb bucket of resin 4 lbs of gelcoat 50 meters of mat ( http://tinyurl.com/aqe73 ) 10 meters of cloth (http://tinyurl.com/bpbcy ) 10 meters of cloth ( http://tinyurl.com/7mdyh ) + an appropriate quantity of hardener and release for a pair Incase you are curious ( you seem to know something about horns ): The horn is a Tractrix type straight midrange horn for an 8" driver w. a cutoff freq. at 300 Hz.. Either way be sure to roll out all the voids and consolidate the lay-up really well. Any voids are going to add unwanted color. Ideally I would vacuum bag the mat/roving lay-up. Keep the temperatures fairly low and cut back some on the MEK (catalyst) to extend your working time long enough to get the bag pulled before the resin kicks.. The vacuum is to drive the airbubbles out of the cast ? I have a couple of vacuum pumps from scrapped vacuum bagging machines ( industrial models for food products ) I might be able to make something usable from those.. Thanks for the guidance so far.. /peter |
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Glenn Ashmore wrote:
That VAT really kills you guys. They will raise it next year here in Germany. The year after, government will be bankrupt. :-( Ni-****edoff-ck -- Motormodelle / Engine Models: http://www.motor-manufaktur.de Ellwe 2FB * VTM 87 * DLM-S3a * cubic more to come ... |
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Q wrote:
although the resin seems to be cheaper at the local home depot wannabe.... I wouldn't take that risk. You don't know how old the home dept's one is, and you also can't select between different "pot time". Just checked, they say R&G is good for fiberglas stuff. .... and Wacken is good for music. :-) Nick -- Motormodelle / Engine Models: http://www.motor-manufaktur.de Ellwe 2FB * VTM 87 * DLM-S3a * cubic more to come ... |
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"Nick Müller" skrev i en meddelelse ... Glenn Ashmore wrote: That VAT really kills you guys. They will raise it next year here in Germany. The year after, government will be bankrupt. :-( You think its bad in Germany?.. Try 25% on everything, like here.. And no, its not lower on food like it is on your side of the Border.. The fuel prices are rediculous too.. Diesel fuel costs about 5 US$ per gallon here and the price keeps going up at a scary rate... I was thinking of converting the van to run on plant oil, but unlike Germany, the plant oil for automotive use is taxed like diesel here, so if you want the conversion to pay off in an economical sense you need to cheat the tax people ( this is relatively easy with the plant oil trick, but damned expensive if you get caught ) Maybe its time to become a religious organisation and see about getting a tax exempt like that amusement park in the US I heard about recently.. /peter |
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"Q" skrev i en meddelelse ... Maybe its time to become a religious organisation and see about getting a tax exempt like that amusement park in the US I heard about recently.. He http://www.usatoday.com/travel/news/...k_x.htm?csp=34 /peter |
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On Sun, 17 Jul 2005 02:38:04 +0200, "Q" wrote:
Any clue if boatwax will work? There are lots of things that will work, but you'd need to do more experimenting with them. The special purpose waxes aren't much more expensive than car wax, floor wax, etc. But for two parts, you could skip the wax altogether if you use a secure layer of PVA. PVA is regular (white) wood glue ?... I could add a little destilled water and spray it on PolyVinyl Alcohol. A liter of it should be plenty for your project. If you can't find a local place to buy proper supplies, just take some empty bottles and a box of donuts to a local fiberglass shop. Hopefully one that's used to building and prepping their own molds. Someone mentioned using babypowder on the mold as a release.. Will that work? I can't imagine how. I'm guessing that you'll be brushing gelcoat onto your prepped mold. Whatever's under your brush strokes can't be disturbed. This might be a good time to mention that gelcoat isn't really necessary. You could brush on a layer of resin instead, let dry, then start laminating. You'd probably get a bit more print-through, and you'd have to paint the finished horns. I could integrate a quickrelease fitting for the airhose in the mold, so I can blow air between the mold and the piece. That could help a lot in the worst case, but shouldn't be necessary if you do the prep right. If the horn is going to have a long throat like the one in the photo, then put any extra time into making that area nice. As much taper as you can, straight and shiny surface, heavy PVA. I could do just a few layers on the mold, let it harden and add more layers after I remove it from the mold... This would help the shrinking problem to some degree, or am I way off track ? That might help a little, but you could be surprised how much a part that isn't fully cured will distort if it's unsupported and you add thick laminations. So long as the mold has been tested to make sure it will release cleanly, I'd finish laminating the part while still on the mold, and then let it cure for at least a day before releasing. Glenn's advice was very good, it's obvious he has some experience. I only disagreed on a couple of minor points - vacuum bagging, not worth the trouble IMO for two relatively small parts. Ditto for roving. I'd get some heavy mat (random strands bonded with a resin-soluble binder). You can split it into thinner layers if you like. You can wet it in place, but if it were me I'd lay the mat onto a flat, clean and non-absorbent surface like Formica, wet it out fully and quickly, and then pick up the slab of gooey glass and apply to the mold. As the binder dissolves, the mat can be stretched to fit contours. So your minimum shopping list could be: PVA, resin (promoted), catalyst, mat, acetone, brushes and rollers. BTW, getting polyester resin on your skin isn't anything to worry about. If it was I'd be dead by now. :-) Washing your hands with acetone is *not* a good idea, although it's done all the time. FWIW, my shop once made an assortment of horns (a few dozen of each size) much like the one in your photo. The largest was about 4 feet tall. We used heavy gelcoat, one layer of chopped glass strand (from a big machine), fitted Divinicell foam bonded over the flat areas, and then more chopped glass over the whole thing. Wayne |
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" Maybe its time to become a religious organization and see about getting a
tax exempt like that amusement park in the US I heard about recently.. Just register as a boatbuilder. That is a non-profit organization if ever there was one. :-) -- Glenn Ashmore I'm building a 45' cutter in strip/composite. Watch my progress (or lack there of) at: http://www.rutuonline.com Shameless Commercial Division: http://www.spade-anchor-us.com |
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"wmbjk" skrev i en meddelelse ... On Sun, 17 Jul 2005 02:38:04 +0200, "Q" wrote: Any clue if boatwax will work? There are lots of things that will work, but you'd need to do more experimenting with them. The special purpose waxes aren't much more expensive than car wax, floor wax, etc. But for two parts, you could skip the wax altogether if you use a secure layer of PVA. I found a source for it, so it wont be a problem.. PolyVinyl Alcohol. A liter of it should be plenty for your project. If you can't find a local place to buy proper supplies, just take some empty bottles and a box of donuts to a local fiberglass shop. Hopefully one that's used to building and prepping their own molds. Hmmmm... Donuts?... I am in Denmark.. The only place to get donuts is Mc Donalds, but I get your point.... Over here stuff like that is usually solved with a sixpack of beer :-) This might be a good time to mention that gelcoat isn't really necessary. You could brush on a layer of resin instead, let dry, then start laminating. You'd probably get a bit more print-through, and you'd have to paint the finished horns. Gelcoat is available in smaller quantities, so that wont be a problem.. I think the Gelcoat I can get locally is white though.. I could integrate a quickrelease fitting for the airhose in the mold, so I can blow air between the mold and the piece. That could help a lot in the worst case, but shouldn't be necessary if you do the prep right. If the horn is going to have a long throat like the one in the photo, then put any extra time into making that area nice. As much taper as you can, straight and shiny surface, heavy PVA. It seems that my plan is to pain the mold with a couple layers of regular turpentine based paint, wax it and coat with PVA... Glenn's advice was very good, it's obvious he has some experience. I only disagreed on a couple of minor points - vacuum bagging, not worth the trouble IMO for two relatively small parts. Ditto for roving. I'd get some heavy mat (random strands bonded with a resin-soluble binder). I like the idea of less things to go wrong or stick to the resin :-) You can split it into thinner layers if you like. You can wet it in place, but if it were me I'd lay the mat onto a flat, clean and non-absorbent surface like Formica, wet it out fully and quickly, and then pick up the slab of gooey glass and apply to the mold. As the binder dissolves, the mat can be stretched to fit contours. So your minimum shopping list could be: PVA, resin (promoted), catalyst, mat, acetone, brushes and rollers. Sounds what we used to do with wallpaperglue, chickenwire and old newspapers in kindergarten :-) BTW, getting polyester resin on your skin isn't anything to worry about. If it was I'd be dead by now. :-) Washing your hands with acetone is *not* a good idea, although it's done all the time. Hmmm.... I work in the food processing industry and the cleaning products and desinfectants are hard on my hands as is.. Good thing about it is that I can get "free" rubber gloves.. FWIW, my shop once made an assortment of horns (a few dozen of each size) much like the one in your photo. The largest was about 4 feet tall. We used heavy gelcoat, one layer of chopped glass strand (from a big machine), fitted Divinicell foam bonded over the flat areas, and then more chopped glass over the whole thing. I decided to try this.. I usually make horns etc. from wood, but theres a lot of work involved when you have to do everything by hand... Seeing that I may end up having to make 40 more of these things the fibreglass seems like a good solution.. /peter |
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These are approx. 4 times the size... So if I order: 10 lb bucket of resin 4 lbs of gelcoat 50 meters of mat ( http://tinyurl.com/aqe73 ) 10 meters of cloth (http://tinyurl.com/bpbcy ) 10 meters of cloth ( http://tinyurl.com/7mdyh ) + an appropriate quantity of hardener and release for a pair I think you will need more resin than that. While a circular horn will not resonate as much as a flat sided one you will still need a fair amount of mass when your low end is around 300hz.. Look at product # 1901541 on page 7 of the fabrics. That is the roving I was talking about to build up the mass and strength. You probably won't need as much of the woven cloth because that only goes on the inner and outer layers. You only need a little MEK-P catalyst as you use only 5 -10 ml per liter of resin. The vacuum is to drive the airbubbles out of the cast ? I have a couple of vacuum pumps from scrapped vacuum bagging machines ( industrial models for food products ) I might be able to make something usable from those.. What the vacuum does is uniformly press the laminations against the mold producing the densest possible layup. If you have the pump you can jerry rig almost everything else but the process takes a bit of practice. You may not want to risk it for your first time. Polyester sets up in 15 -30 minutes depending on the temperature, amount of MEK-P and the mass of the layup so you don't have a lot of time to get the bag on. You can read some basics of it on my web site in the Hull section. If you want to try it get some 4 to 6 mil clear poly builders film for the bag and seal it with vacuum tape. prod # 3901701 on page 2 of the vacuum technology page. You will also need a breather mat prod# 3901801 on page.3 and a peel ply like 3901851. Alternately you can use nylon flag bunting or taffeta for the peel ply. You can usually find that on the remnant counter at a fabric store. -- Glenn Ashmore I'm building a 45' cutter in strip/composite. Watch my progress (or lack there of) at: http://www.rutuonline.com Shameless Commercial Division: http://www.spade-anchor-us.com |
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"Glenn Ashmore" skrev i en meddelelse newsCvCe.171910$sy6.164164@lakeread04... " Maybe its time to become a religious organization and see about getting a tax exempt like that amusement park in the US I heard about recently.. Just register as a boatbuilder. That is a non-profit organization if ever there was one. :-) Yup... Seems that this project is going to cost a few boatbucks already :-) Btw: I looked at your boat project page and I must say: DAMN, thats a big project ! Wouldnt mind seeing some pics of the finished boat once you get that far... Looks impressive.. Maybe you could enter the Tall Ships Race ( Formerly known as the Cutty Sark Tall Ships Race ) and stop by here.. I took some pictures of some of the ships that were racing here last year.. The most interesting ship was probably the russian ship Sedov, built in 1921. The ship is made from steel plates that are riveted, not welded. Theres a few pics of it he http://www.naeslund.dk/peter/foto/tsr04/IMG_0046.JPG http://www.naeslund.dk/peter/foto/tsr04/IMG_0050.JPG More pics of some of the larger vessels here http://www.naeslund.dk/peter/foto/tsr04/page_01.htm Thanks again for your help... I will report back when I get my hands on the resin etc. /peter |
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"Nick Müller" skrev i en meddelelse ... I wouldn't take that risk. You don't know how old the home dept's one is, and you also can't select between different "pot time". True... Just checked, they say R&G is good for fiberglas stuff. Excellent.. ... and Wacken is good for music. :-) I doubt it would be considered good for Schlager fans :-) /peter |
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Make sure that the gloves you get are immune to the resins in the
fiberglass. Gloves bonded to your hands is worse than washing in acetone. Q wrote: "wmbjk" skrev i en meddelelse ... On Sun, 17 Jul 2005 02:38:04 +0200, "Q" wrote: Any clue if boatwax will work? There are lots of things that will work, but you'd need to do more experimenting with them. The special purpose waxes aren't much more expensive than car wax, floor wax, etc. But for two parts, you could skip the wax altogether if you use a secure layer of PVA. I found a source for it, so it wont be a problem.. PolyVinyl Alcohol. A liter of it should be plenty for your project. If you can't find a local place to buy proper supplies, just take some empty bottles and a box of donuts to a local fiberglass shop. Hopefully one that's used to building and prepping their own molds. Hmmmm... Donuts?... I am in Denmark.. The only place to get donuts is Mc Donalds, but I get your point.... Over here stuff like that is usually solved with a sixpack of beer :-) This might be a good time to mention that gelcoat isn't really necessary. You could brush on a layer of resin instead, let dry, then start laminating. You'd probably get a bit more print-through, and you'd have to paint the finished horns. Gelcoat is available in smaller quantities, so that wont be a problem.. I think the Gelcoat I can get locally is white though.. I could integrate a quickrelease fitting for the airhose in the mold, so I can blow air between the mold and the piece. That could help a lot in the worst case, but shouldn't be necessary if you do the prep right. If the horn is going to have a long throat like the one in the photo, then put any extra time into making that area nice. As much taper as you can, straight and shiny surface, heavy PVA. It seems that my plan is to pain the mold with a couple layers of regular turpentine based paint, wax it and coat with PVA... Glenn's advice was very good, it's obvious he has some experience. I only disagreed on a couple of minor points - vacuum bagging, not worth the trouble IMO for two relatively small parts. Ditto for roving. I'd get some heavy mat (random strands bonded with a resin-soluble binder). I like the idea of less things to go wrong or stick to the resin :-) You can split it into thinner layers if you like. You can wet it in place, but if it were me I'd lay the mat onto a flat, clean and non-absorbent surface like Formica, wet it out fully and quickly, and then pick up the slab of gooey glass and apply to the mold. As the binder dissolves, the mat can be stretched to fit contours. So your minimum shopping list could be: PVA, resin (promoted), catalyst, mat, acetone, brushes and rollers. Sounds what we used to do with wallpaperglue, chickenwire and old newspapers in kindergarten :-) BTW, getting polyester resin on your skin isn't anything to worry about. If it was I'd be dead by now. :-) Washing your hands with acetone is *not* a good idea, although it's done all the time. Hmmm.... I work in the food processing industry and the cleaning products and desinfectants are hard on my hands as is.. Good thing about it is that I can get "free" rubber gloves.. FWIW, my shop once made an assortment of horns (a few dozen of each size) much like the one in your photo. The largest was about 4 feet tall. We used heavy gelcoat, one layer of chopped glass strand (from a big machine), fitted Divinicell foam bonded over the flat areas, and then more chopped glass over the whole thing. I decided to try this.. I usually make horns etc. from wood, but theres a lot of work involved when you have to do everything by hand... Seeing that I may end up having to make 40 more of these things the fibreglass seems like a good solution.. /peter |
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On Sun, 17 Jul 2005 17:40:53 +0200, the opaque "Q" clearly
wrote: Maybe its time to become a religious organisation and see about getting a tax exempt like that amusement park in the US I heard about recently.. He http://www.usatoday.com/travel/news/...k_x.htm?csp=34 Bloody 'ell. When will the insanity stop? sigh - Gently-used Firestone tires for sale at discount! ----------- http://diversify.com Website Application Programming |
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"RoyJ" skrev i en meddelelse ink.net... Make sure that the gloves you get are immune to the resins in the fiberglass. Gloves bonded to your hands is worse than washing in acetone. Hmmmm... Interesting idea.. Latex coated hands... Sounds kinky :-) /peter |
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