what glue is best for a job im doing

[trikershaun]

hi im building a coach build van and am  at the point of putting the polystyrene on the wall,  trying to do the same thing as a caravan walls 'tight and part of the strength,

but don't know what the experts use on caravans. the walls are grp with wood ribs.  hope some one can help thank you

[Guest Tracker]

Aluminium / polystyrene / wood board composite coachbuilt side panels are 'vacuum' bonded in the factory and it is the removal of the air which gives the tightly laminated panel as much as the glue itself which gives the panel it's structural rigidity.

 

I don't know what glue they use but I suspect it is sprayed on in copious quantities to get the even universal coverage needed prior to bonding.

 

Heaven knows how you can replicate this process other than by laying the panels on the floor and applying an even weight all over it - and maybe someone else will know which adhesive to use?

 

But I wish you luck and every success!

[Derek Uzzell]

There’s an “Insulating a Motorcaravan” chapter in John Wickersham’s “Build Your Own Motorcaravan” book (I would have thought this book ought to be a ‘must have’ for your project) that should be useful, though it doesn’t cover sticking polystyrene to GRP or wood.

 

Caravans and motorhomes with expanded polystyrene or Styrafoam as body-panel insulation will (as Tracker says) normally use bonded composite panels that won’t be available to the one-off vehicle DIY-er. So I don’t believe it’s realistic to expect to be able to DIY-copy exactly how caravans are made commercially.

 

Personally, I’d use a polyurethane adhesive, (Sikaflex 252 is probably as good a choice as any) putting plenty of adhesive ‘dots’ on the back of the polystyrene panel before pushing it firmly against the face of the GRP wall. Then I’d do something similar to attach the panels that will form the inner wall coverings. You won’t get the full strength of a fully bonded composite body-panel, but the end-result should still be pretty stiff.

 

I don’t know what you’ve employed to stick the wooden ribs to the GRP wall panels (which I assume are flat, not seriously curved), but, as long as that adhesive is suitable, I’d be tempted to use it for the polystyrene too.

 

Sika and Henkel-Loctite produce adhesives that are widely used by caravan/motorhome manufacturers and I found both companies helpful when I’ve sought advice in the past. These are their websites:

 

http://gbr.sika.com/

 

http://www.loctite.co.uk/cps/rde/xchg/henkel_uke/hs.xsl/homepage.htm

[Dave Newell]

When we re-skinned our last coachbuilt motorhome (1990 Autohomes Highwayman) we glued the new aluminium skin on with Sikaflex 252. We applied it to the polystyrene insulation in copious amounts with hand operated guns (by the fifth tube your wrists will be knackered) then spread it out with a wide flat paint scraper then applied the skin and clamped it in place using a few large flat boards and held it all in place with ladders, planks etc wedged between the boards and the wall of the workshop. The finish wasn't 100% perfect but it was plenty good enough.

 

D.

[Derek Uzzell]

It would be interesting to know how Shaun is building this vehicle.

 

Standard commercial practice involves an inside-out approach, putting a floor on a chassis, then fixing all the 'furniture' to the floor, installing all the wiring, plumbing and appliances, and finally fixing in place pre-constructed walls and roof.

 

I'm not sure this is a practical sequence for the DIY-er though and I suspect Shaun may be building outside-in, constructing the body-shell first and then doing all the rest from inside. Either way, polyurethane adhesives are likely to be the best type to use.

[trikershaun]

Derek Uzzell - 2010-09-23 9:12 AM It would be interesting to know how Shaun is building this vehicle. Standard commercial practice involves an inside-out approach, putting a floor on a chassis, then fixing all the 'furniture' to the floor, installing all the wiring, plumbing and appliances, and finally fixing in place pre-constructed walls and roof. I'm not sure this is a practical sequence for the DIY-er though and I suspect Shaun may be building outside-in, constructing the body-shell first and then doing all the rest from inside. Either way, polyurethane adhesives are likely to be the best type to use.

i was thinking the same but was unsure, polyurethane in a tub, the swift caravan i puled apart fo the knowledge of construction and the inside parts for mine, lol i found that that was poly glue but was not sure of it at the time, now im  sure, so spray glue polystyrene to the grp and then polyurethane to the ribs i think that should do fo that thank you pople for your help

construction is simple really, ally frame for floors with angle ion frame bolted to that in order to hold a ply wood floor, then iv put pre made in 3 parts wood frame in shed  and bolted and screwed and clued with a very strong but cheaper type of grab glue, its as good as silca flex and cheaper £7 against £12 last time i looked(100 pound spent on that so far) then made some 8 x 4 grp sheets and clued and riveted and screwed that on and sealed from in side the joins and that that so far, sold the dodge 50 and using that cash to build a basic starter van for me.

[Guest peter]

Whatever adhesive you use DO NOT use any with a solvent base, with Polystyrene as it will be disolved.