See the topic a little further down "gas shock fix"...
I am still trying to find what I and Sika Corp consider to be the correct adhesive...Sikaflex or Sikafast. Others have used different adhesive with apparent good results.
The factory used Sikafast 252 as the adhesive beneath the flimsy piece of aluminum they used.
The following is what Sika Corp had to say:
"You had mentioned that the one substrate is potentially luan. Luan is typically thin plywood with a layer of gelcoat similar to fiberglass. Do you believe this is the substrate in question as opposed to vinyl or plastic? If so, we typically do quite well with gelcoats be it fiberglass or luan. In which case, I think your best bet would be SikaFast-3121 or SikaFast-3131S. These are our 2-component acrylics. The problem with something like Sikaflex-252 is that it is a 1-component polyurethane that requires moisture to cure. You would not be able put adhesive over the entire area of the steel, only about 1 inch around the perimeter. Ideally with any polyurethane products you would also want about 1/8" thick bondline. With the 2-component acrylics you can go much lower (0.030") as well as cover the entire area. However, our 2-component acrylics can be expensive and difficult to obtain (plus a static mixers and a special air gun are required). Conversely, polyurethanes will require more surface pre-treatments. We use to sell a version of SikaFast-3121 that came in a 50 mL cartridge that would use a small manual gun. However, I think that we have discontinued this item.
In summary, if this is indeed gelcoated luan, I would recommend one of the following:
1. (Best Option) Scuff the gelcoat and steel. Clean with IPA and allow 10 minutes of flash time. Bond together with either SikaFast-3121 or SikaFast-3131S. Make sure to avoid excessive "squeeze out."
2. (Acceptable Option). Scuff the gelcoat and steel. Apply Sika Aktivator by wiping on followed by wiping off on both the gelcoat and steel. Wait 10 minutes. Apply Sika Primer-206 G+P to both substrates. Wait 10 minutes. Apply Sikaflex-255 FC (Sikaflex-252 could possibly work, but Sikaflex-255 FC is a stronger stiffer product that I believe would provide much better results). Maintain a bondline thickness of ~1/8".
In regards to obtaining product, quite often will not break cases. As each
distributor & accessories is run independently, it will vary from location to location. To find a distributor, you can call our customer service at 800-688-7452 (you will need to select Option #2) or visit our website here for a partial listing:
http://www.sikaindustry.com/ind/ipd-star-distributor-agrpg.htm"
Some Sika products can be found on e-bay, but so far, I've not found # 255, nor Sikafast 3121 or 3131, nor have I found small quantities available from the distributors.
A request to purchase Sika from DRV has been ignored by Ryan Miller.
Regards
Gemstone