We are making a secondary bond between 2 mouldings, that have polished gel coat finish. Previous source of neutral color bonding paste, that was easily pigmented to same colour as mouldings can no longer supply, so need to make our own.
Anyone have any bright ideas as to an appropriate filler to make bonding paste, that can also be pigmented to help with secondary bond on our coloured mouldings?
Ive had good luck with 1/4" chopped fibers, 5 minute epoxy, and black dye. 3M DP100 (structural adhesive) is the epoxy I used for bonding at my old job.
Im guessing any epoxy will do the trick though.
One of the problems with epoxy is the cost…poly bonding paste we have been using up to now, wasnt that expensive and could be easily coloured.
Main difficulty though is that after secondary bond is made on bike fuel tanks we make, we seal the tanks with a mix of poly resin and gel-coat, and there may be problems with this if epoxy bonding paste was used.
In regard to cost, 5kg of poly bonding paste costs approx £19-20, and is ready to use after adding MEK, the same amount of epoxy is going to be over £100, and needs the addition of filler material, and an expensive activator.
Is it smart to use poly to build fuel tanks?
wow, you secondary bond parts using PER paste??? I’ve done strength tests and the epoxy is many times stronger…
Not had a single problem, and I dont know of any original GRP fuel tank fitted by manufacturer, that was made with anything other than poly!
Wouldnt be that hard to double the cost of the products we are making by using epoxy, but as there is no good commercial reason for this, dont think we are going to be trying that just yet.
I know boat fuel tanks (diesel) are all poly & gel coated inside. Fresh water tanks are normally epoxy (food grade) and left unpainted or painted with food grade PU paints. Waste tanks can be done either way. Dunno about gas fuel tanks but there have been problems with Ethanol blends and gel coats used in fiberglass tanks causing major problems. Ethanol turns the gelcoat to goo and clogs fuel lines, filters, injection sytems and carbs. If it gets into the engine it wreaks havoc with valves and piston rings. The ethanol can also attack rubber parts in the fuel system turning them to mush.
Might try these guys:
http://www.adtechplastics.com/pc-130-36-marine-bond-fill.aspx
Heres their UK distributors:
Aero Consultants/UK
13/14 Clifton Rd
Huntingdon Cambs PE29 7EJ
441480432111
Sil-Mid Ltd.
2 Roman Way
Coleshill West Midland B46 1HG
84451301110
Thanks JRL…I will give them a call. Not had any problems with ethanol fuels here in the UK, as amounts used in blends here are pretty low, but have heard of major hassles with UK made GRP tanks that have been exported to US.
Guy I know makes tanks used for methanol burning race bikes, and these are made with vinyl-ester resin system. This means the tanks are far more long lasting than poly, but in some cases must be replaced after a couple of years due to problems.