Kagor 0 Posted April 17, 2020 Hi, I have a fairly well preserved 205 GTI, 1989, purchased and used in the nordics, with salty roads. While I was doing some bumper job on it I also had a view of the body, inside the wheelhouses. 98% of the underbody coating (underseal) is in good shape. I found two small cracks with surface rust inside one of the front wheelhouses, which were wire brushed, cleaned, rust converted (works as a primer too) and painted with multiple layers. Now, the question is; what kind of protective coating would you apply, localy, on the painted spot inside the wheelhouse and what would you do to the rest of the underside to prolong the protection of the factory underseal? The car is currently not in need of a total rest, but a good maintenance is best. I have done some research and there are so many brands which I don't have any experience with. Discovered two types of coatings, bitumen based petroleum materials (stays sticky) and rubberized coatings (dries out and turns into a rubber layer). Also a polyurethane type, which becomes a thin flexible layer after drying. What I don't want to do is to apply something that dissolves or make the factory coating brittle and porous. In case any of you know the kind of chemical compound used in the factory underseal, I would like to know. This wiki page gives a general idea over the rustproofing materials, https://en.wikipedia.org/wiki/Rustproofing I have also read that some car brands, questionable if old peugeots are concerned, are not liking petroleum based coatings for a reason. Thank you! Share this post Link to post Share on other sites
Kagor 0 Posted April 30, 2020 (edited) I have found these two candidates. Dinitrol 700 https://www.dinitrol.com/produkt/dinitrol-700/ and Teroson SB 3120 https://www.henkel-adhesives.com/pl/en/product/protective-coatings/teroson_sb_3120.html Does anybody have experience with repairing and applying this on the factory underbody coating? Some earlier information over here, https://www.205gtidrivers.com/forums/topic/90428-what-can-i-use-for-covering-this/ Thanks! Edited April 30, 2020 by Kagor Share this post Link to post Share on other sites
DamirGTI 341 Posted April 30, 2020 (edited) I used all of the three types , polyurethane sealer , rubberized and bitumen undercoating .. haven't experienced any reaction with the OE coating with either . I did however had some adhesion and surface/layer cracking problems with one brand of rubberized undercoating .. was some cheap pretty much unknown brand (and possibly expired shelf life of the product , these do have shelf life and date stamp under the cans so it's good practice to check if it's still good for use) Can't remember what is actually OE type coating , but some kind of PVC/polyurethane and possibly some asbestos too .. Dinitrol products are excellent quality , worked with Dinitrol stuff on a few bodywork repair and restoration cars during the years and really liked it .. so definitely recommended . Also : Henkel/Teroson , Wurth , Forch , Loctite - all good quality stuff . Depending on how much of the bodywork you wish to treat , for larger and longer areas pick the stuff in the UBS cans rather than spray/rattle cans , as the stuff in a spray is much more diluted/thinned thus you need to buy more cans .. for small areas spot repair spray form of either product will do . With the UBS cans you'll obviously need an air compressor and UBS spray gun to apply the stuff . As with anything bodywork wise , preparation is most important : https://www.mig-welding.co.uk/stonechip.htm D Edited April 30, 2020 by DamirGTI Share this post Link to post Share on other sites
Philpooma 30 Posted April 30, 2020 I found this company and have used their products on two restorations. I cant find the quote after quickly looking at their web site but I remember that at the time they supplied Volvo cars and their products are designed tested for Scandinavian winters https://www.noxudolusa.com Share this post Link to post Share on other sites
