im getting ready to do my first gloss coat and had just a couple of questions about sanding. I am a little confused about the rubbing compund. should i use 3m heavy duty rubbing compund? or the surfboard polish that they have on fiberglasssupply.com . Also, how do you apply the rubbing compound and what do you use to apply it with. By the way i checked the archives and still dont really understand this.
thanks,
George
Before glossing, sand everything to 180 grit. Wipe with acetone and tape off. I strongly recommend that you use Kokua’s mixture added to the gloss resin which is 10% styrene and 5% SA, 1 1/2% cat. Cut the tapelines with a fine file and go 220-320 on the line only. Sand any zits/bumps at 320 (lightly). Progress to 400 then 600. Wash everything off good and dry it. I get good polishing results using West Marine compound (#190183 -not the liquid, $8) and a 10" wool pad @ 1000 rpm. Apply the compound with a small piece of a towel and do 12" sq. overlapping sections. Finish with an automotive paste wax (not the silicone type). Remember that gloss resin has a longer cure time, so watch the gel time in the cup to tell you when to pull the tape. Get the tape off as soon as possible since the added styrene will bleed out the adhesive from most tapes.
George,
After I have glossed. I Wet sand with 320, 400, then 600. Wash the board off with a very getle mix of dishwashing detergent and water.
Now for the fun part. I start with the 3M heavy duty rubbibg compund. You apply this with a wool buffing bonnet and a power sander. Attach the wool bonnet to your sander ( I use a 7 inch makita). Take the rubbing compund and squirt out just a few dollpos per square foot of board. You really only want to di about 2 sqare feet at a time. Spread the compound around the area with the sander, and then at the lowest speed setting, and with moderate to firm pressure begin going over the area you just covered. You should press hard and then gradually lighten up. Always continuosly move the sander in smooth even pases side to side to completely work through the rubbing compound. It is actually fairly simple. You will be amazed at how quickly the board glosses up.
Do the entire board in this fashion. I then switch to the 3M Medium cut and repeat the process, and then to the Fine cut and repeat. after that I’ll use a product called 3M Finnesse it and again repeat the process. And finally I use 3M Marine wax to provide a final protecting shield agaisnt scratches.
You could skip the Medium, fine, and Finness steps if you want, but it does truly make a difference.
I stay with the 3M family for compatibility reasons and plus they are readily available in my area. You can get them at better auto parts stores…Napa for instance.
Drew
Howzit Drew, Have you ever tried Shurlustre rubbing compound, pretty much the industry standard. Costs about $ 16.00 a gallon, plus it works great. Aloha, Kokua
I have been meaning to. But whenever I get around to glossing I always forget to acquire some. Plus I have not found it to be available around where I live. Not that I’ve looked or anything. maybe it might suit me to stop being lazy.
Do they make it in different grades? Medium Fine, etc?
Drew
Howzit Drew, One of the best things about Shurlustre is it works as both a course and fine compound. I don’t know where you’re located but Fiberglass Hawaii carries it and I’m sure it’s available from another supplier. Aloha, Kokua
thanks. But how does one product work as both coarse and fine. Seems like it can only be one or the other.
Drew
Howzit Drew, How it works, I'm not sure. I used to use both course and fine compounds until I was ordering from F.H. and they said I should try shurlustre, I did and have never looked back. Aloha, Kokua
One way that a compound, (or cabinet sandpaper as well) can work both as a course and fine abrasive, is that it starts out course, then breaks down as you progress. At the end, you’re using a very fine abrasive that just keeps getting finer. Doug