birdybiker66 Posted September 25, 2013 Share Posted September 25, 2013 I'm fitting an aerial to the MH roof when i get chance and am using sikaflex 512 , will it be sufficient to rough up the bonding area with sandpaper or similar, any tips welcome, thanks, Dave Link to comment Share on other sites More sharing options...
Guest peter Posted September 25, 2013 Share Posted September 25, 2013 De-grease it as well. with white spirit or meth's. Link to comment Share on other sites More sharing options...
birdybiker66 Posted September 25, 2013 Author Share Posted September 25, 2013 Thanks, I forgot that bit, cheers. Link to comment Share on other sites More sharing options...
hughman Posted September 25, 2013 Share Posted September 25, 2013 I'm not sure white spirit will degrease anything - it always seems quite oily to me. I'd use meths or surgical spirit instead. Link to comment Share on other sites More sharing options...
birdybiker66 Posted September 26, 2013 Author Share Posted September 26, 2013 I have some brake cleaner which is very effective, I'll try that. One more thing, do I need to seal the gap between inner and outer skin, there's no mention of it in the instructions! I thought maybe some type of waterproof tape. ? Link to comment Share on other sites More sharing options...
RogerC Posted September 26, 2013 Share Posted September 26, 2013 My brother in law who fits alarms/electrics etc to motorhomes for a living said simply clean the area using a degreaser.....such as brake cleaner which has been suggested above to ensure a grease/polish free contact area. He said there is no need to 'roughen' the area. Link to comment Share on other sites More sharing options...
Guest peter Posted September 26, 2013 Share Posted September 26, 2013 birdybiker66 - 2013-09-26 8:03 AM I have some brake cleaner which is very effective, I'll try that. One more thing, do I need to seal the gap between inner and outer skin, there's no mention of it in the instructions! I thought maybe some type of waterproof tape. ?You could put some silicone sealant round the edge of the hole. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted September 27, 2013 Share Posted September 27, 2013 Dave SIKA does market a preparation product, but it's not cheap and 1-litre is the minimum quantity: http://www.ukfixings.com/product/342/525/Sika-Cleaner-205 You don't say what type of aerial you'll be gluing to the roof, but you need to remember that a joint made with Sikaflex-512 should not be too thin. A 2mm thickness of adhesive is recommended. Guidance on Sikaflex-512 usage can be found by using the following link and clicking on the top entry that's retrieved headed "[PDF] Sikaflex®-512 Caravan - Sika UK" http://www.google.co.uk/#q=sikaflex+512+joint+thickness Surface preparation advice is "Clean surfaces are important. If a key is required use a polyester scouring pad or fine abrasive paper. For degreasing and final cleaning use a spirit based solvent that contains no oils (eg. Sika Remover-208 or white spirit). For maximum bond use Sika Cleaner-205 which contains an adhesion promoter." Link to comment Share on other sites More sharing options...
crinklystarfish Posted September 27, 2013 Share Posted September 27, 2013 Don't use white spirit to prepare the area. White spirit is quite good at removing 512 as has been said. Neither do you need to key the area. 512 is quite happy on clean / dry grp or painted aluminium. If the area is a bit grimy, it's best just to polish it back with a bit of cutting compound but make sure you remove all traces of the compound before applying 512. I've also used a dab of cellulose thinners to good effect but you must let the thinners fully evaporate (wipe with a paper towel to help) before using the 512. Having said all that, not sure I'd be bonding an aerial to the roof. Not sure why you would need to? Link to comment Share on other sites More sharing options...
birdybiker66 Posted September 27, 2013 Author Share Posted September 27, 2013 Thanks for all the pointers, appreciated, I'm fitting a status vision which has to have a hole drilled and it comes with a wafer thin foam gasket which I don't trust. Thanks, Dave Link to comment Share on other sites More sharing options...
pepe63xnotuse Posted September 27, 2013 Share Posted September 27, 2013 Hi Dave.. Have you got any other, ageing seals that you can trim out and re-cap, while you're at it?... Because opening a fresh tube of Sika', just to run a seal around one tele aerial, does seem a bit of a waste..because it doesn't "keep" once opened. (..it's a bit like having ready-mix dropped of...it's always best to somewhere else for it go, just in case you've ordered too much! (lol) ) I resealed a large seam on our roof a while back(with 512)..and while I was at it, I tidied up all the original, manky looking seams around the roof vents... (..even if it's not "needed", at least it gives extra peace of mind.. ;-) ) Link to comment Share on other sites More sharing options...
birdybiker66 Posted September 27, 2013 Author Share Posted September 27, 2013 Thanks Pepe, I had a quick look up there and thought " these look a bit manky!" so yes i will, I'm guessing cut as much out as is reasonably possible with a craft knife or similar? Dave Link to comment Share on other sites More sharing options...
pepe63xnotuse Posted September 27, 2013 Share Posted September 27, 2013 Yes I just cut away any lumpy bits and carefully trimmed under the vent frames slightly(nothing too "invasive"!) ...wiped it all down, then re-beaded it.. Link to comment Share on other sites More sharing options...
birdybiker66 Posted September 27, 2013 Author Share Posted September 27, 2013 Thanks for that, "nothing too invasive" explains it perfectively, cheers Link to comment Share on other sites More sharing options...
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