alanmac Posted May 21, 2012 Share Posted May 21, 2012 I have a small job to do on the 'van which involves the use of sikaflex. My question is - the existing adhesive ? Is there a suitable solution which will dissolve/clean this old adhesive ? Or is it a case of elbow grease and cloths ? Hope you can help - thank you Alan Link to comment Share on other sites More sharing options...
t5topcat Posted May 21, 2012 Share Posted May 21, 2012 I seem to remember from my classic car days that "panel degreaser" does the job. Thats depending on which sikaflex you are using, there are many.Try the Sika website I think they have a FAQ page. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted May 21, 2012 Share Posted May 21, 2012 If the original adhesive is also Sikaflex (or a similar polyurethane adhesive/sealant) then you'll need to remove the stuff 'mechanically'. SIKA does market a cleaner (Sika Remover-208) but this is designed to remove UNCURED Sikaflex from glass, metal, brushes or tools. Once these adhesives have cured, the only realistic way to remove the stuff is by carefully cutting/scraping it off. t5topcat mentions SIKA's FAQ advice. This says 13) How do I remove / clean excess Sika products (cured or uncured)? Product that has already cured must be removed mechanically with a razor blade, grinding wheel, etc. Several products such as Sika® Remover-208, Sika® Hand Cleaner towels, or mineral spirits remove uncured material the best. Alcohols should never be used around the bond area of cured or uncured material as they may inhibit or reverse the cure of Sikaflex® products. Link to comment Share on other sites More sharing options...
JohnP Posted May 21, 2012 Share Posted May 21, 2012 Agree with Derek that once the Sikaflex has cured there is no way that it can be returned to its liquid state. A sharp knife, chisel etc can be used to carefully remove the old adhesive. The cleaner Sikaflex market is only used in surface preparation and for removing surplus adhesive before it cures. Link to comment Share on other sites More sharing options...
Guest 1footinthegrave Posted May 21, 2012 Share Posted May 21, 2012 Other posters are correct, gently does it with something like the edge of a stanley blade for removal of the old stuff. What a pity this product does not come in smaller tubes, my guess is most of it ends up in landfill as even doing your best to reseal the tube has always left me with a solid unusable product very soon after opening usually within a few weeks. Or perhaps these forums could act as a way of passing a tube around before it cures in the tube, and is then about as much use as an ashtray on a motorbike. ;-) Link to comment Share on other sites More sharing options...
pepe63xnotuse Posted May 22, 2012 Share Posted May 22, 2012 I've recently rebeaded a large seam on the roof of our van,using Sika'512..and in our case,it *was* just a matter of cutting and chamfering out the original "Sika' like" sealant with a sharp blade... (..even if there was something that would "dissolve/loosen" the sealant,personally I'd be concerned that some of that may creep into and remain in the seam and undermining the "new" bead). As 1foot' says,Sika' won't last in the tube,so if need be, "create" jobs for what's left?.. To make full use of our tube,I also trimmed off the "snotty bits" of original,still pliable "beding mastic" from around the roof vents etc and rebeaded those. (..and I'm glad to say that the Sika' didn't discolour/react to the any of the original sealants). Link to comment Share on other sites More sharing options...
alanmac Posted May 25, 2012 Author Share Posted May 25, 2012 Thanks to you all for the useful imformation. NOW if only the weatrher holds up ! Link to comment Share on other sites More sharing options...
Brian Kirby Posted May 25, 2012 Share Posted May 25, 2012 Have a word with Sika's technical department and explain what you have to do. If you are confident that the original sealant was a Sika product, and you know/can find out which, it may not be necessary to fully remove all traces of it, as I believe that in some cases the new will happily bond with the old. However, this will depend on the actual product, its condition and age. The modified polyurethane sealants are supposed to have a service life of 25-30 years, so if their advice is that the bond with the old should be good, there is no great need to worry about the original sealant causing the new to degrade prematurely - unless your van is a true veteran, that is! :-D If the joint has cracked open it is more likely, IMO, to be due to poor initial execution, chemical attack of some kind, or possibly because the degree of movement at the joint exceeds the elasticity of the seal (i.e. bad design), than because the sealant itself is life expired. Link to comment Share on other sites More sharing options...
whiskers Posted May 26, 2012 Share Posted May 26, 2012 I use Marineflex. It stays usable much longer than Sikaflex does in the tube. I obtain it from these people.-- www.marinemastics.com/marine-flex.html Link to comment Share on other sites More sharing options...
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