On 2006-11-21 09:19:43 +0000, "Antix" said:

Thanks Andy,
so the question now is which resin ! Screwfix do the Fischer Epoxy
which needs a special tool to ensure the two parts are ejected from the
tube simultaneously (buggers!), or there's the non-epoxy
stuff....Vinylester resin which is part cement and doesn't need a
special tool...choices choices !

I wonder if my 3 year old son's arm will fit through the hole....


Ant.

I looked at Screwfix's different options and decided to pick from the
Fischer range, mainly because I could get all of the product
information from Fischer's web site to answer a few questions that I
had.

The options are

- go for one of the larger cartridge types such as V360 (Screwfix
88507 £16.49) or P380 (42772 £13.00). However, these require an
injection gun costing £50 (35237) for the V360 or £22.49 for the one
for P380. The V360 resin is better because it has a mortar component,
but the cost for a small project is then getting expensive.

- go for one or two of the small 100ml cartridges (51021 at £11.99).
These are more expensive in terms of price/quantity, but are complete
and ready to go. You fit the nozzle and twist the base. The resin is
the mortar type.

I wasn't sure when I was going to use the technique again or for that
matter, whether it would work adequately, so I wasn't going to invest
£50 in the special gun. I think that next time I have a significant
project I might well, though.

I was using 10mm fixings going quite deep and was able to get 8 or so
fixings from a 51021 100ml tube. I had made a reasonable estimate
and bought an extra tube just in case. Since Screwfix has a 30 day
return policy, over-ordering doesn't matter. I had a tube left over
and frankly have kept it.
The nozzles are single use only. However, because I was using several
packs at one go, I was able to transfer a nozzle and end up with some
spares.

So the steps a

- Identify the stud size that will fit the holes in the bracket. You
will need a masonry drill 2mm diameter larger.

- Choose studs that are of suitable length. It's better to avoid
drilling all the way into the cavity if you can because you will tend
to inject some resin all the way through. However, that's not
horrendous - you just need to slowly withdraw the nozzle while
injecting. You can cut the studs with a hacksaw and that's easier
done before fitting.

- For accuracy, I would recommend making up a template from a piece of
ply or similar. Using the bracket, mark and drill holes in the ply
of the size of the holes in the bracket.

- Tape the template to the wall (level it with a spirit level) and mark
the holes. Remove template.

- Drill the holes.

- Vacuum them out thoroughly. This is important. If you hold the
nozzle of the cleaner hose up to the wall at each hole put only half
covering the hole, the rush of air in clears the dust out well.

- I would suggest doing them all at once, injecting the resin and
inserting each stud with twisting motion. Important. If there isn't
some ooze of resin from the hole then pull out stud and put in more
resin.

- Clean off any excess resin

- Locate the template back onto the studs making sure that all go
through. This ensures that they are all located exactly correctly and
that the bracket will fit. Remember that each stud has +/- 1mm of
movement.

- Leave for 24hrs

- Then you can attach the bracket.