im looking for a grinder to use for my laps… any help would be appreciated. what do most of u guys use and where can i find it. thanks dj
If you are talking about the FIRST lap: Most board builders in the industry use a mini-die grinder set up with a 3 inch disk. This tool is pneumatic so that may be limiting. I have seen a few shops that use the Dremel Moto Tool using a 1/2 inch diameter barrel sander with the coarsest sleeve (looks like 60 grit). Using the edge of your hand as a guide it is ideally possible to walk around the board one time and have the lap knocked down. I say “ideally” because the lap has to be really neat and have a flowing line with now undulations. Caution: look closely at your work (unfortunately it will most likely appear after hotcoat) and see if your tool made any microcracks at the lap line. These can be disolved away with certain chemicals. This machine operation is sometimes followed up by an abrasive/chemical combo that can completely melt the lap into the adjacent foam. If you are talking about the SECOND lap: 8" disk grinder with a pretty firm disk. 60 grit is good for starters and the higher the speed the more accurate the surface. The higher the speed, the more likely you could get a burn-through, so be careful. Hope this helps, good luck.
Hi You guys have got me worried, I don’t grind or sand any of my laps but resin it only 2/3 the way round leaving the last bit un- resined. When I do the next layer I just resin the remaining un resined bit though the layer that I am doing with a bit of extra resin. What should I be doing. Or do some of you guys use this method aswell.
interesting. Never thought of doing that. Makes sense. I would only caution that leaving a portion of the first lap dry would possibly create a line where the first lay-up cured. this would be no good for color work. Also there might be a a structural issue becuase the faom has cured on one side of the first lay-up and the other is cured at a later time. It’s deffinitely a unique way to laminate. Not one that I will be trying, but interesting nonetheless. Normally you would do one of 2 methods… a “cut-lap” or a “free-lap”. A) tape the deck and cut the first layer to go over the tape by about a inch. Once the first layer is semi-cured cut at the outside edge of the tape layer to trim a nice cut-lap. Use this method if you are doing color work or usign volan glass, or just want to make sure that you leave a very clean lap edge. B) a free lap is not taped off. Rather you trim the cloth much as you would in the first process, just take more care to trim a closer lap edge in the cloth. Use this method of you are using clear resin and normal cloth, “S” or “E” cloth. For more interesting reading, just type in cutlap in the archives Drew
Milwaukee and Sioux Tool Co. both make a “close quarter drill” - you can fit one of those mini grinding discs on it. Max speed is 1300 RPM which gives great control when grinding laps, glassed on fins or ding repairs. http://www.powertoolservices.com/tool_section/0375-7.htm
I don’t know where the Milwaukee is made… I had heard that they were outsourcing to Mexico… Here’s another one by “American Tool” in China! LOL! http://www.brandsonsale.com/38rigandrilr.html
Sioux high speed… http://miva3.synergydns.net/Merchant2/merchant.mv?Screen=PROD&Store_Code=packard&Product_Code=125002&Category_Code=snding-sad
Scroll down after opening this link and check the 2" & 3" backing pads. They fit the chucks on any of the above angle drills. http://www.fiberglasssupply.com/Product_Catalog/ShapingTools/shapingtools.html
to prevent discolorazation,is it best to use the grinder at high speed, or at a slower speed to keep it cooler??
thanks a bunch. im gonna go with the one from fiberglass supply. one more question. what grit do u guys use. im thinking 60 or 80. dk
Try thi smethod guys… I bet you guys haven’t heard of it have you?.. Tape off the rail(a bit higher than you would if you were doing a cut lap. Cut the lap 1/4 of an inch below the tape line. ANy excess resin an cloth strands will lay over the tape. You can then trim any strands easiers than if you didn’t tape off. If you plaster down any fibers, then cut then off. there will be so minimal lap grinding needed. I know it sounds strange because you would think I am just doing a free lap. But for some reason the tape helps lift off any strands and permits easy cutting of the ones left. I saw Joe Roper due thin once back in the day.