Best wood primer of old, unpainted dried out external wooden window sills?
Some of the windows in the South side of my house have wooden frames and sills, and on the outside of the house, most of the paint has flaked off, leaving bare wood that is severely sun-baked and weather-beaten, yet thankfully, with almost no rot. I have recently bought this house and I now want to paint the external side of these frames to prolong their life as much as possible. What is a good primer to use? What soaks into dry wood well, and stays put, even over the duration of a long hot summer or three? I'm under the impression that aluminium primer is good. I guess it must soak into dry wood well, because it is very runny, compared to other wood primers, some of which have the consistency of cheese spread! It seems to cost more than other primers, which also suggests to me that it might be particularly good for some applications. Anyone got any strong opinions on this? Al. |
Best wood primer of old, unpainted dried out external wooden window sills?
"AL_n" wrote in message ... Some of the windows in the South side of my house have wooden frames and sills, and on the outside of the house, most of the paint has flaked off, leaving bare wood that is severely sun-baked and weather-beaten, yet thankfully, with almost no rot. I have recently bought this house and I now want to paint the external side of these frames to prolong their life as much as possible. What is a good primer to use? What soaks into dry wood well, and stays put, even over the duration of a long hot summer or three? I'm under the impression that aluminium primer is good. I guess it must soak into dry wood well, because it is very runny, compared to other wood primers, some of which have the consistency of cheese spread! It seems to cost more than other primers, which also suggests to me that it might be particularly good for some applications. Anyone got any strong opinions on this? You could do worse than going to a big paint manufacturer and buying their best quality exterior paint. They do actually carry out research and development and test and improve their paints. Dulux (ICI) Weathershield for instance is a good paint system. You must _not_ buy your paint from a retail/diy outlet because even if it is labelled Dulux Weathershield (for instance) it is water based and a totally different paint to the oil based trade paint from the trade supplier. The quality of diy paint is always compromised in order to give it 'marketable' qualities like easy brush washing or non drip consistency. Alternatively you can stick with more traditional oil paints and get a good result. Metallic primers have been used for years as yacht paints, with instructions to start with thinned primer then apply several more coats of primer before undercoating. Gloss, gloss, gloss is another method I have seen used on historic buildings with traditional paints, whereby you just use gloss from first to last coat and keep going till you have the finish you want. I would treat the bare wood with cuprinol and let it dry well before you paint. Tim W |
Best wood primer of old, unpainted dried out external woodenwindow sills?
On 17/09/2010 04:13, AL_n wrote:
Some of the windows in the South side of my house have wooden frames and sills, and on the outside of the house, most of the paint has flaked off, leaving bare wood that is severely sun-baked and weather-beaten, yet thankfully, with almost no rot. I have recently bought this house and I now want to paint the external side of these frames to prolong their life as much as possible. What is a good primer to use? What soaks into dry wood well, and stays put, even over the duration of a long hot summer or three? I'm under the impression that aluminium primer is good. I guess it must soak into dry wood well, because it is very runny, compared to other wood primers, some of which have the consistency of cheese spread! It seems to cost more than other primers, which also suggests to me that it might be particularly good for some applications. Anyone got any strong opinions on this? Al. 2 part wood hardener. Having tried all sorts over the years, that's a very strong opinion :-) http://www.screwfix.com/prods/63540/...Hardener-500ml If the paint is off and you're seeing that grey look, it's the perfect opportunity, and you'll probably never have to paint again. The wood doesn't have to be "rotten" to benefit. I've even used it on brand new wood. |
Best wood primer of old, unpainted dried out external woodenwindow sills?
stuart noble wrote:
On 17/09/2010 04:13, AL_n wrote: Some of the windows in the South side of my house have wooden frames and sills, and on the outside of the house, most of the paint has flaked off, leaving bare wood that is severely sun-baked and weather-beaten, yet thankfully, with almost no rot. I have recently bought this house and I now want to paint the external side of these frames to prolong their life as much as possible. What is a good primer to use? What soaks into dry wood well, and stays put, even over the duration of a long hot summer or three? I'm under the impression that aluminium primer is good. I guess it must soak into dry wood well, because it is very runny, compared to other wood primers, some of which have the consistency of cheese spread! It seems to cost more than other primers, which also suggests to me that it might be particularly good for some applications. Anyone got any strong opinions on this? Al. 2 part wood hardener. Having tried all sorts over the years, that's a very strong opinion :-) http://www.screwfix.com/prods/63540/...Hardener-500ml If the paint is off and you're seeing that grey look, it's the perfect opportunity, and you'll probably never have to paint again. The wood doesn't have to be "rotten" to benefit. I've even used it on brand new wood. Good idea. I used this sort of product once on rotting wood, and it really turns the surface into a wood/resin composite and totally stabilises it. After that any sort of grain filling primer for outdoor use will be fine. |
Best wood primer of old, unpainted dried out external wooden window sills?
Sikkens Rubbol is a good product. -- Airport Shuttle '' (http://www.yourcityride.com) Message origin: TRAVEL.com |
Best wood primer of old, unpainted dried out external wooden window sills?
The Natural Philosopher wrote in
: 2 part wood hardener. Having tried all sorts over the years, that's a very strong opinion :-) http://www.screwfix.com/prods/63540/...-Rot-Wood-Hard ener-500ml If the paint is off and you're seeing that grey look, it's the perfect opportunity, and you'll probably never have to paint again. The wood doesn't have to be "rotten" to benefit. I've even used it on brand new wood. Good idea. I used this sort of product once on rotting wood, and it really turns the surface into a wood/resin composite and totally stabilises it. After that any sort of grain filling primer for outdoor use will be fine. Thanks to all, for the advice thus far. Yes indeed, the woodwork has gone grey, and the grain is also standing out, almost as if it has been sand- blasted. So I will take the advice, and try the said product. Thanks. Al |
Best wood primer of old, unpainted dried out external woodenwindow sills?
On Sep 17, 8:53*am, "Tim W" wrote:
You must _not_ buy your paint from a retail/diy outlet because even if it is labelled Dulux Weathershield (for instance) it is water based and a totally different paint to the oil based trade paint from the trade supplier. The quality of diy paint is always compromised in order to give it 'marketable' qualities like easy brush washing or non drip consistency. You could do a lot worse than seeking out your local trade paint supplier -- which may be a more difficult exercise than you'd think. Around here a lot of the painters and decorators actually use local retail stores to buy their paint,presumably on attractive terms. That allows them to direct individual clients to the retail store in question to see wallpaper patterns etc. And significant numbers also use the paint manufacturers' "trade centres" -- where increasingly they sell to the public as well -- at an exorbitant price. I was asked today to pick up an order at the local Dulux Trade Centre. Almost £50 for five litres of emulsion paint. All I can say is that I certainly would not even think of buying there for myself. Running a caravan site we have trade accounts with a number of suppliers of various sorts. Our fire extinguisher contract is with a company who also (interesting combination of interests!) run the best trade paint centre in the area. I've been dealing with them for thirty years. Their fire-extinguisher maintenance charges are approximately half the cost of the big "national" companies and the whole exercise is trouble-free. Their paint prices are about a third of the price of the big names and the materials they supply are always fit for the job. And they do the whole range -- automobile and agricultural as well (just in case you want to repaint your little grey Fergie in exactly the authentic shade!). No fancy showroom -- no showroom of any sort. Just a trade counter. And they're quite happy to supply over it to anyone -- though we obviously have an account with them anyway. Companies like that are worth their weight in gold. |
Best wood primer of old, unpainted dried out external woodenwindow sills?
Hi Stuart
2 part wood hardener. Having tried all sorts over the years, that's a very strong opinion :-) http://www.screwfix.com/prods/63540/...-Rot-Wood-Hard... [...] Fine, but that Ronseal stuff isn't 2-part, is it? I'd buy a two-part version if I came across it... J^n |
Best wood primer of old, unpainted dried out external woodenwindow sills?
On 17/09/2010 22:11, jkn wrote:
Hi Stuart 2 part wood hardener. Having tried all sorts over the years, that's a very strong opinion :-) http://www.screwfix.com/prods/63540/...-Rot-Wood-Hard... [...] Fine, but that Ronseal stuff isn't 2-part, is it? On reading the COSH data, maybe not, but then why the big plastic cap on the can? That usually contains the hardener IME. Can't vouch for it if it's not 2 part but maybe it works well enough with an acetone solvent I'd buy a two-part version if I came across it... J^n |
Best wood primer of old, unpainted dried out external woodenwindow sills?
On 18 Sep, 08:27, stuart noble wrote:
On 17/09/2010 22:11, jkn wrote: Hi Stuart 2 part wood hardener. Having tried all sorts over the years, that's a very strong opinion :-) http://www.screwfix.com/prods/63540/...-Rot-Wood-Hard... [...] Fine, but that Ronseal stuff isn't 2-part, is it? On reading the COSH data, maybe not, but then why the big plastic cap on the can? That usually contains the hardener IME. Can't vouch for it if it's not 2 part but maybe it works well enough with an acetone solvent strewth.... the big plastic cap is the "handy" kettle in which to pour some (single part) hardener (styrene) and dip your (single use) brush..... where's this "2 part wood hardener" then?? gotta proper link???? Jim K |
Best wood primer of old, unpainted dried out external woodenwindow sills?
On 18/09/2010 08:58, Jim K wrote:
On 18 Sep, 08:27, stuart wrote: On 17/09/2010 22:11, jkn wrote: Hi Stuart 2 part wood hardener. Having tried all sorts over the years, that's a very strong opinion :-) http://www.screwfix.com/prods/63540/...-Rot-Wood-Hard... [...] Fine, but that Ronseal stuff isn't 2-part, is it? On reading the COSH data, maybe not, but then why the big plastic cap on the can? That usually contains the hardener IME. Can't vouch for it if it's not 2 part but maybe it works well enough with an acetone solvent strewth.... the big plastic cap is the "handy" kettle in which to pour some (single part) hardener (styrene) and dip your (single use) brush..... I would have thought the acetone would attack the plastic, otherwise why package it in a metal container? where's this "2 part wood hardener" then?? gotta proper link???? Jim K I thought the Ronseal link was it. Last time I used a wood hardener (can't remember the brand) it was 2 part, and the plastic cap contained a tube of catalyst. If I needed a lot of this stuff I'd approach a GRP supplier because I think on porous material the drying time with a single pack might be a good deal longer than stated on the can. |
Best wood primer of old, unpainted dried out external woodenwindow sills?
On 18/09/2010 08:58, Jim K wrote:
On 18 Sep, 08:27, stuart wrote: On 17/09/2010 22:11, jkn wrote: Hi Stuart 2 part wood hardener. Having tried all sorts over the years, that's a very strong opinion :-) http://www.screwfix.com/prods/63540/...-Rot-Wood-Hard... [...] Fine, but that Ronseal stuff isn't 2-part, is it? On reading the COSH data, maybe not, but then why the big plastic cap on the can? That usually contains the hardener IME. Can't vouch for it if it's not 2 part but maybe it works well enough with an acetone solvent strewth.... the big plastic cap is the "handy" kettle in which to pour some (single part) hardener (styrene) and dip your (single use) brush..... where's this "2 part wood hardener" then?? gotta proper link???? That would be he http://tinyurl.com/36d4sy7 (or http://www.screwfix.com/prods/51811/Sealants-Adhesives/Fillers/Wood-Fillers/Ronseal-High-Performance-Wood-Filler-550g Ronseal also used to do "Wood Preservative Tablets" which they sold alone or as part of a boxed "Ronseal Wood Repair System", which also included the 2-part filler and the wood hardener. The idea was that you drilled into affected wood, shoved one of these tablets down the hole and then filled over. The idea was that they released preservative deep within the wood if moisture levels increase. I used them once or twice and I didn't seem to have any problems; however they don't seem to be available any more. David |
Best wood primer of old, unpainted dried out external woodenwindow sills?
stuart noble wrote:
On 18/09/2010 08:58, Jim K wrote: On 18 Sep, 08:27, stuart wrote: On 17/09/2010 22:11, jkn wrote: Hi Stuart 2 part wood hardener. Having tried all sorts over the years, that's a very strong opinion :-) http://www.screwfix.com/prods/63540/...-Rot-Wood-Hard... [...] Fine, but that Ronseal stuff isn't 2-part, is it? On reading the COSH data, maybe not, but then why the big plastic cap on the can? That usually contains the hardener IME. Can't vouch for it if it's not 2 part but maybe it works well enough with an acetone solvent strewth.... the big plastic cap is the "handy" kettle in which to pour some (single part) hardener (styrene) and dip your (single use) brush..... I would have thought the acetone would attack the plastic, otherwise why package it in a metal container? styrene is not acetone, and acetone does not attack polythene, It comes in polythene bottles. |
Best wood primer of old, unpainted dried out external wooden window sills?
stuart noble wrote in news:RRZko.39817
: On reading the COSH data, maybe not, but then why the big plastic cap on the can? That usually contains the hardener IME. Can't vouch for it if it's not 2 part but maybe it works well enough with an acetone solvent I think the large plastic cap is simply so that you can dip a brush onto it, as the can iteself, probably has a small screw cap. I think it's the wood *filler* that is 2-part and has a tube of hardener with it. There may have been some confusion between the catalysing filler "hardener" and the (one-part) wood "hardener". Incidentally, I once used liquid wood hardener on some window frames that had started to rot (after removing all of the loose/soft wet rot. The kit also contained wood preservative pellets that were inserted into the wood after drilling holes. I did the job very carefully, according to instructions. It may have delayed the continuation of the spread of the rot very very slightly, but it by no means halted it, and the rot was back with a vengeance before one year had passed. Perhaps that's why they no longer sell those kits... Al |
Best wood primer of old, unpainted dried out external woodenwindow sills?
On 18/09/2010 23:57, The Natural Philosopher wrote:
stuart noble wrote: On 18/09/2010 08:58, Jim K wrote: On 18 Sep, 08:27, stuart wrote: On 17/09/2010 22:11, jkn wrote: Hi Stuart 2 part wood hardener. Having tried all sorts over the years, that's a very strong opinion :-) http://www.screwfix.com/prods/63540/...-Rot-Wood-Hard... [...] Fine, but that Ronseal stuff isn't 2-part, is it? On reading the COSH data, maybe not, but then why the big plastic cap on the can? That usually contains the hardener IME. Can't vouch for it if it's not 2 part but maybe it works well enough with an acetone solvent strewth.... the big plastic cap is the "handy" kettle in which to pour some (single part) hardener (styrene) and dip your (single use) brush..... I would have thought the acetone would attack the plastic, otherwise why package it in a metal container? styrene is not acetone, and acetone does not attack polythene, It comes in polythene bottles. Which begs the question why this Ronseal stuff, consisting mainly of acetone, comes in a metal container. |
Best wood primer of old, unpainted dried out external woodenwindow sills?
stuart noble wrote:
On 18/09/2010 23:57, The Natural Philosopher wrote: stuart noble wrote: On 18/09/2010 08:58, Jim K wrote: On 18 Sep, 08:27, stuart wrote: On 17/09/2010 22:11, jkn wrote: Hi Stuart 2 part wood hardener. Having tried all sorts over the years, that's a very strong opinion :-) http://www.screwfix.com/prods/63540/...-Rot-Wood-Hard... [...] Fine, but that Ronseal stuff isn't 2-part, is it? On reading the COSH data, maybe not, but then why the big plastic cap on the can? That usually contains the hardener IME. Can't vouch for it if it's not 2 part but maybe it works well enough with an acetone solvent strewth.... the big plastic cap is the "handy" kettle in which to pour some (single part) hardener (styrene) and dip your (single use) brush..... I would have thought the acetone would attack the plastic, otherwise why package it in a metal container? styrene is not acetone, and acetone does not attack polythene, It comes in polythene bottles. Which begs the question why this Ronseal stuff, consisting mainly of acetone, comes in a metal container. Ronseal always comes in tins. Otherwise you wouldn't be able to say 'does what it says on the tin! Simples! |
Best wood primer of old, unpainted dried out external woodenwindow sills?
On 18/09/2010 17:07, Jim K wrote:
On 18 Sep, 14:22, wrote: On 18/09/2010 08:58, Jim K wrote: On 18 Sep, 08:27, stuart wrote: On 17/09/2010 22:11, jkn wrote: Hi Stuart 2 part wood hardener. Having tried all sorts over the years, that's a very strong opinion :-) http://www.screwfix.com/prods/63540/...-Rot-Wood-Hard... [...] Fine, but that Ronseal stuff isn't 2-part, is it? On reading the COSH data, maybe not, but then why the big plastic cap on the can? That usually contains the hardener IME. Can't vouch for it if it's not 2 part but maybe it works well enough with an acetone solvent strewth.... the big plastic cap is the "handy" kettle in which to pour some (single part) hardener (styrene) and dip your (single use) brush..... where's this "2 part wood hardener" then?? gotta proper link???? That would be hehttp://tinyurl.com/36d4sy7 (or http://www.screwfix.com/prods/51811/Sealants-Adhesives/Fillers/Wood-F... erm.... that's filler not preservative?? Thoughts that what he meant - it comes in two parts, of which one is a sachet of catalyst "hardener". Never heard of a wood preservative in two parts. David |
Best wood primer of old, unpainted dried out external wooden window sills?
Lobster wrote:
On 18/09/2010 17:07, Jim K wrote: On 18 Sep, 14:22, wrote: On 18/09/2010 08:58, Jim K wrote: On 18 Sep, 08:27, stuart wrote: On 17/09/2010 22:11, jkn wrote: Fine, but that Ronseal stuff isn't 2-part, is it? On reading the COSH data, maybe not, but then why the big plastic cap on the can? That usually contains the hardener IME. Can't vouch for it if it's not 2 part but maybe it works well enough with an acetone solvent strewth.... the big plastic cap is the "handy" kettle in which to pour some (single part) hardener (styrene) and dip your (single use) brush..... where's this "2 part wood hardener" then? gotta proper link???? That would be hehttp://tinyurl.com/36d4sy7 erm.... that's filler not preservative?? Thoughts that what he meant - it comes in two parts, of which one is a sachet of catalyst "hardener". Never heard of a wood preservative in two parts. He doesn't want filler for trowelling on, he wants a liquid for painting on the wood, and which then sets hard. I think what he means is some kind of runny resin which, after you've mixed in the catalyst, stays liquid for long enough to soak into the wood before it cures. I guess he thinks one-part hardeners won't go hard enough. |
Best wood primer of old, unpainted dried out external woodenwindow sills?
On 19/09/2010 15:40, Lobster wrote:
On 18/09/2010 17:07, Jim K wrote: On 18 Sep, 14:22, wrote: On 18/09/2010 08:58, Jim K wrote: On 18 Sep, 08:27, stuart wrote: On 17/09/2010 22:11, jkn wrote: Hi Stuart 2 part wood hardener. Having tried all sorts over the years, that's a very strong opinion :-) http://www.screwfix.com/prods/63540/...-Rot-Wood-Hard... [...] Fine, but that Ronseal stuff isn't 2-part, is it? On reading the COSH data, maybe not, but then why the big plastic cap on the can? That usually contains the hardener IME. Can't vouch for it if it's not 2 part but maybe it works well enough with an acetone solvent strewth.... the big plastic cap is the "handy" kettle in which to pour some (single part) hardener (styrene) and dip your (single use) brush..... where's this "2 part wood hardener" then?? gotta proper link???? That would be hehttp://tinyurl.com/36d4sy7 (or http://www.screwfix.com/prods/51811/Sealants-Adhesives/Fillers/Wood-F... erm.... that's filler not preservative?? Thoughts that what he meant - it comes in two parts, of which one is a sachet of catalyst "hardener". Never heard of a wood preservative in two parts. David I've used a 2 part wood hardener, and it's a hardener, not a preservative. Liquid resin, paste hardener in the plastic cap, not unlike the cans of fibreglass resin from an auto shop. |
Best wood primer of old, unpainted dried out external wooden window sills?
"stuart noble" wrote in message ... On 18/09/2010 23:57, The Natural Philosopher wrote: stuart noble wrote: On 18/09/2010 08:58, Jim K wrote: On 18 Sep, 08:27, stuart wrote: On 17/09/2010 22:11, jkn wrote: Hi Stuart 2 part wood hardener. Having tried all sorts over the years, that's a very strong opinion :-) http://www.screwfix.com/prods/63540/...-Rot-Wood-Hard... [...] Fine, but that Ronseal stuff isn't 2-part, is it? On reading the COSH data, maybe not, but then why the big plastic cap on the can? That usually contains the hardener IME. Can't vouch for it if it's not 2 part but maybe it works well enough with an acetone solvent strewth.... the big plastic cap is the "handy" kettle in which to pour some (single part) hardener (styrene) and dip your (single use) brush..... I would have thought the acetone would attack the plastic, otherwise why package it in a metal container? styrene is not acetone, and acetone does not attack polythene, It comes in polythene bottles. Which begs the question why this Ronseal stuff, consisting mainly of acetone, comes in a metal container. Solvents usually do come in tins. Even if they don't dissolve the polymer itself they still can strip plasticisers, and also polythene is not stable in sunlight. However, this did not stop us selling IPA in 25 litre plastic drums, but acetone is so volatile we would not have done that. I keep 'nail varnish remover' in the fridge but it still evaporates slowly out of the bottle cap. With Ronseal, the main reason for the tin is probably to make sure the solvent has evaporated before you want to use it again... Same goes for the rusty tins of plastic wood and Nitromors and the always split caps of Araldite tubes... S |
Best wood primer of old, unpainted dried out external woodenwindow sills?
On 19/09/2010 17:46, Ronald Raygun wrote:
Lobster wrote: On 18/09/2010 17:07, Jim K wrote: On 18 Sep, 14:22, wrote: On 18/09/2010 08:58, Jim K wrote: On 18 Sep, 08:27, stuart wrote: On 17/09/2010 22:11, jkn wrote: Fine, but that Ronseal stuff isn't 2-part, is it? On reading the COSH data, maybe not, but then why the big plastic cap on the can? That usually contains the hardener IME. Can't vouch for it if it's not 2 part but maybe it works well enough with an acetone solvent strewth.... the big plastic cap is the "handy" kettle in which to pour some (single part) hardener (styrene) and dip your (single use) brush..... where's this "2 part wood hardener" then? gotta proper link???? That would be hehttp://tinyurl.com/36d4sy7 erm.... that's filler not preservative?? Thoughts that what he meant - it comes in two parts, of which one is a sachet of catalyst "hardener". Never heard of a wood preservative in two parts. He doesn't want filler for trowelling on, he wants a liquid for painting on the wood, and which then sets hard. I think what he means is some kind of runny resin which, after you've mixed in the catalyst, stays liquid for long enough to soak into the wood before it cures. I guess he thinks one-part hardeners won't go hard enough. IMO it's more a question of how long the resin will take to cure when it's applied to a porous surface. Normally you want to get on with the painting without fear of solvent being trapped under the new coating. If 2 part wood hardeners are no longer available I would use a standard polyester resin, although thin layers can still take a few hours to cure in cool conditions. Low viscosity resins and accelerators are available from GRP suppliers if you want to get serious. |
Best wood primer of old, unpainted dried out external wooden window sills?
stuart noble wrote in news:NYrlo.142501
: IMO it's more a question of how long the resin will take to cure when it's applied to a porous surface. Normally you want to get on with the painting without fear of solvent being trapped under the new coating. If 2 part wood hardeners are no longer available I would use a standard polyester resin, although thin layers can still take a few hours to cure in cool conditions. Low viscosity resins and accelerators are available from GRP suppliers if you want to get serious. I trouble with polyester resin, is that the surface remains sticky (i.e., doesn't cure) unless a wax additive is used, and a wax additive will prevent the proper adhesion of any regular paint, as it rises to the surface. I encountered this problem many times when working with GRP. Apart from laboriously removing the wax from the surface prior to painting, the only other solution I recall, was to paint with coloured resin (rather than paint). Al |
Best wood primer of old, unpainted dried out external woodenwindow sills?
On 20/09/2010 10:10, AL_n wrote:
stuart wrote in news:NYrlo.142501 : IMO it's more a question of how long the resin will take to cure when it's applied to a porous surface. Normally you want to get on with the painting without fear of solvent being trapped under the new coating. If 2 part wood hardeners are no longer available I would use a standard polyester resin, although thin layers can still take a few hours to cure in cool conditions. Low viscosity resins and accelerators are available from GRP suppliers if you want to get serious. I trouble with polyester resin, is that the surface remains sticky (i.e., doesn't cure) unless a wax additive is used, and a wax additive will prevent the proper adhesion of any regular paint, as it rises to the surface. I encountered this problem many times when working with GRP. Apart from laboriously removing the wax from the surface prior to painting, the only other solution I recall, was to paint with coloured resin (rather than paint). Al I've never had a problem with the tack, but I've always used a car body filler on top, which I imagine absorbs any uncured resin |
Best wood primer of old, unpainted dried out external woodenwindow sills?
stuart noble wrote:
On 20/09/2010 10:10, AL_n wrote: stuart wrote in news:NYrlo.142501 : IMO it's more a question of how long the resin will take to cure when it's applied to a porous surface. Normally you want to get on with the painting without fear of solvent being trapped under the new coating. If 2 part wood hardeners are no longer available I would use a standard polyester resin, although thin layers can still take a few hours to cure in cool conditions. Low viscosity resins and accelerators are available from GRP suppliers if you want to get serious. I trouble with polyester resin, is that the surface remains sticky (i.e., doesn't cure) unless a wax additive is used, and a wax additive will prevent the proper adhesion of any regular paint, as it rises to the surface. I encountered this problem many times when working with GRP. Apart from laboriously removing the wax from the surface prior to painting, the only other solution I recall, was to paint with coloured resin (rather than paint). Al I've never had a problem with the tack, but I've always used a car body filler on top, which I imagine absorbs any uncured resin If you mix the resin properly there is no tack. Gentle heatgun will always fast cure polyester anyway. Any surplus chemistry can be removed with acetone or similar, but generally not needed. One wonders how so many fibreglass cars and boats ever get painted if the above were in any way true. |
Best wood primer of old, unpainted dried out external woodenwindow sills?
On 20/09/2010 14:26, The Natural Philosopher wrote:
stuart noble wrote: On 20/09/2010 10:10, AL_n wrote: stuart wrote in news:NYrlo.142501 : IMO it's more a question of how long the resin will take to cure when it's applied to a porous surface. Normally you want to get on with the painting without fear of solvent being trapped under the new coating. If 2 part wood hardeners are no longer available I would use a standard polyester resin, although thin layers can still take a few hours to cure in cool conditions. Low viscosity resins and accelerators are available from GRP suppliers if you want to get serious. I trouble with polyester resin, is that the surface remains sticky (i.e., doesn't cure) unless a wax additive is used, and a wax additive will prevent the proper adhesion of any regular paint, as it rises to the surface. I encountered this problem many times when working with GRP. Apart from laboriously removing the wax from the surface prior to painting, the only other solution I recall, was to paint with coloured resin (rather than paint). Al I've never had a problem with the tack, but I've always used a car body filler on top, which I imagine absorbs any uncured resin If you mix the resin properly there is no tack. Gentle heatgun will always fast cure polyester anyway. Any surplus chemistry can be removed with acetone or similar, but generally not needed. One wonders how so many fibreglass cars and boats ever get painted if the above were in any way true. AFAIK tack is common to all polyseter resins, hence the wax additive option for the final coat. Nature of the beast |
Best wood primer of old, unpainted dried out external wooden window sills?
The Natural Philosopher wrote in news:i77ne1$56l$1
@news.albasani.net: If you mix the resin properly there is no tack. Only if it happens to be surfacing resin (containing wax). |
Best wood primer of old, unpainted dried out external woodenwindow sills?
AL_n wrote:
The Natural Philosopher wrote in news:i77ne1$56l$1 @news.albasani.net: If you mix the resin properly there is no tack. Only if it happens to be surfacing resin (containing wax). Ok smartass, what do they put on the surface of fibergalss mouldings that - isn't tacky - takes paint then? |
Best wood primer of old, unpainted dried out external wooden window sills?
The Natural Philosopher wrote in
: Ok smartass, what do they put on the surface of fibergalss mouldings that - isn't tacky - takes paint then? Sorry - I don't share my knowledge with twits who call me smartass. |
Best wood primer of old, unpainted dried out external woodenwindow sills?
AL_n wrote:
The Natural Philosopher wrote in : Ok smartass, what do they put on the surface of fibergalss mouldings that - isn't tacky - takes paint then? Sorry - I don't share my knowledge with twits who call me smartass. So, you don't have a clue then? |
Best wood primer of old, unpainted dried out external woodenwindow sills?
On 20/09/2010 15:16, The Natural Philosopher wrote:
AL_n wrote: The Natural Philosopher wrote in news:i77ne1$56l$1 @news.albasani.net: If you mix the resin properly there is no tack. Only if it happens to be surfacing resin (containing wax). Ok smartass, what do they put on the surface of fibergalss mouldings that - isn't tacky - takes paint then? AFAIK you can only get a full cure by excluding air from the surface, so maybe aly foil would work on a flat area, and be easy enough to remove. I imagine the tacky bit must cure eventually, but probably not in a time suited to a production line. |
Best wood primer of old, unpainted dried out external wooden window sills?
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Best wood primer of old, unpainted dried out external wooden window sills?
stuart noble wrote in news:yeZlo.171648
: I would have thought white spirit could be used, assuming the additive is some kind of mineral wax. If it was soluble in acetone I'm guessing it wouldn't separate out and sit on the surface the way it does. You've got a point. Perhaps it was white spirit that we used to wash it off. It was a long time ago... Al |
Best wood primer of old, unpainted dried out external woodenwindow sills?
stuart noble wrote:
On 20/09/2010 19:28, AL_n wrote: stuart wrote in news:ufNlo.163911$Q_ 2: AFAIK you can only get a full cure by excluding air from the surface, so maybe aly foil would work on a flat area, and be easy enough to remove. I imagine the tacky bit must cure eventually, but probably not in a time suited to a production line. When I worked in GRP (quite a few years ago) we used to use the liquid wax additive and then, once cured, wash the surface wax off with ecetone, and then roughen the surface to provide a key if we needed to apply oil based or water based paint. However, for my window sill job, I guess an easy solution would be to use a coloured resin topcoat (if I can grt hold of a small amount of pigment and not have to buy a large container of it)... Al I would have thought white spirit could be used, assuming the additive is some kind of mineral wax. If it was soluble in acetone I'm guessing it wouldn't separate out and sit on the surface the way it does. I once tried diluting a body filler with gelcoat resin to make it more workable, and to give a longer open time. Can't remember what the outcome was, but it should work in theory. I laid up some GF stuff - very roughly using ordinary resin. I juts sanded it, applied a further coat of resin, sanded that with wet and dry, wiped it with acetone and sprayed car primer on it. Nothing special, no tackiness, no problem. |
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