Quick question: I have an opportunity to pick up a variable speed polisher that only goes up to 2500 rpm; or a variable speed polisher that only goes up to 1750 rpm for a great price. What is the best rpm for sanding a hot coat and what is the best rpm for polishing a gloss coat? I want to make sure that I get the most versatile unit for the money. Any tips on polishing a gloss coat? I’ve only done sanded hot coats to date and I want to make sure that I go about a gloss coat the right way. Thanks guys.
The higher speed one might be better for sanding and the lower speed for buffing but the pad you use, the sandpaper grit and the polishing compounds play a part as well. I should think that either machine would work - actual RPMs may be splitting hairs. After knocking down the high spots by machine, if you use a longblock for hand sanding (I use a coarse sanding belt cemented to a rubber block) you will have less of a chance of leaving ripples under the gloss coat. Be careful however because too much pressure with super coarse grit on a 4 oz glass job can actually damage the glass. On the gloss coat, even after you filter the resin, you will have to wet sand any zits and bumps and eventually work down to 600 grit before buffing with polishing compound. Most guys cut and cement the wet/dry paper to the pad for this. There are different grits of polishing compound but an automotive rubbing compound (or even toothpaste!) will work. I dilute it with water, put it in a squeeze bottle and squirt a little on the board and hit it with the polishing pad until it shines. You are about to find out why a gloss and polished board costs a bit more than a sanded finish!>>> Quick question: I have an opportunity to pick up a variable speed polisher > that only goes up to 2500 rpm; or a variable speed polisher that only goes > up to 1750 rpm for a great price. What is the best rpm for sanding a hot > coat and what is the best rpm for polishing a gloss coat? I want to make > sure that I get the most versatile unit for the money. Any tips on > polishing a gloss coat? I’ve only done sanded hot coats to date and I want > to make sure that I go about a gloss coat the right way. Thanks guys.
Also - Herb Spitzer says that the yellow $40.00 machine from Harbor Freight has served him well. Perhaps he can elucidate on the pads, compounds, etc. that he recommends?>>> The higher speed one might be better for sanding and the lower speed for > buffing but the pad you use, the sandpaper grit and the polishing > compounds play a part as well. I should think that either machine would > work - actual RPMs may be splitting hairs. After knocking down the high > spots by machine, if you use a longblock for hand sanding (I use a coarse > sanding belt cemented to a rubber block) you will have less of a chance of > leaving ripples under the gloss coat. Be careful however because too much > pressure with super coarse grit on a 4 oz glass job can actually damage > the glass. On the gloss coat, even after you filter the resin, you will > have to wet sand any zits and bumps and eventually work down to 600 grit > before buffing with polishing compound. Most guys cut and cement the > wet/dry paper to the pad for this. There are different grits of polishing > compound but an automotive rubbing compound (or even toothpaste!) will > work. I dilute it with water, put it in a squeeze bottle and squirt a > little on the board and hit it with the polishing pad until it shines. You > are about to find out why a gloss and polished board costs a bit more than > a sanded finish!
Also - Herb Spitzer says that the yellow $40.00 machine from Harbor > Freight has served him well. Perhaps he can elucidate on the pads, > compounds, etc. that he recommends? John, I hope Herb has some input when he gets back from Vegas. Thank you for your response – However, it prompted another question. Please bear in mind that I am self taught with an occasional question asked to some partners that are very cool about sharing their knowledge. The question is: Huh?! What do you mean “filter the resin”??? Share with me buddy! Magoo
Oh, one final question John: Do you know what brand or model sander Herb was talking about? I plan on going to Harbour Freight this week. Thanks, M
I have it all ,but prefer my P-20SB PRO,with my modifications to it,next would be my BOSCH in a close second.Then my un-SKILL-100…Sanders,again I won’t die sanderless.I have the best,but my favorite is my $40.00 dollar cheapo from Harbor Freight Tools.It’s the yellow bodied 7"-er sander/polisher…I bought 3 thinking THAT THEY WOULD BURN OUT QUICKLY ,but I’m still with the first one ,and I haven’t even changed the brushes yet.THIS IS MY #1 SANDER.Herb. (from 7/18/01 @6:44PM - JM)>>> Oh, one final question John: Do you know what brand or model sander Herb > was talking about? I plan on going to Harbour Freight this week. Thanks, M
Oh, one final question John: Do you know what brand or model sander Herb > was talking about? I plan on going to Harbour Freight this week. Thanks, M …Archive it ,Herb.
Magoo - I’ve taken the liberty of pasting Herb’s post re: yellow cheapo sander. Here is a reference by Steve from 7/18/01 @6:44PM re: “straining” the gloss resin through panty hose. I’ve used the little cone shaped funnels with openings covered by fine mesh for filtering resin. It’s just to get little particles out that cause zits and bumps in the gloss coat. I get them cheap at the local paint store. Check the archives under “glossing” - there are a lot of pointers from different people. I only wish I had access to this site when I started! Here is Steve’s post: I haven’t heard many of you guys give this tip: to avoid gloss coats zits, strain the gloss resin thru a panty hose. It lets you start with 320 and not have to scrape zits with a razor blade or work out the zits with the 320–thus ensuring not sandi9ng thru gloss resin. Another tip. Use two steps in buffing: a good cutting compound and then a finishing compound to get that shiny gloss. PS. Gloss coats are a elbow grease intensive anyhow.
I USE PAINT STRAINERS…check the archives for ,“brush cleaning”,Herb
Quick question: I have an opportunity to pick up a variable speed polisher > that only goes up to 2500 rpm; or a variable speed polisher that only goes > up to 1750 rpm for a great price. What is the best rpm for sanding a hot > coat and what is the best rpm for polishing a gloss coat? I want to make > sure that I get the most versatile unit for the money. Any tips on > polishing a gloss coat? I’ve only done sanded hot coats to date and I want > to make sure that I go about a gloss coat the right way. Thanks guys. Generally, grits of 100 to 220 are run at about 5,000 rpms (hot coat). Be sure and get a “Power Pad - soft” — its the best, accept no substitutions. 320 grits and higher (often used on gloss coats) are run at 2500 or less. High rpms with fine sandpaper generate a lot of heat – keep it moving or you will get “burns” – tan spots – or worse. Use Silicone Carbide paper. Tip – sand paper that is torn on the edges – even a little bit – means trouble. Remove it and put on a clean sheet. If you want the most versital sander – get the Milwaukee 7068 variable speed – 0 to 6000 RPM – its about $160 new – it will take you anywhere you want to go. As for gloss coats: I sand them out with 320 grit and the power pad – then, I move to 600 on a pad called a “Disket” which is stiffer and flater and use it at real slow speed with some water on the board. Then go to 1000 wetsand and a hand sand – polish with polishing compound (keep it out of the sun) polish off dry compound with wool bonet. The look is totally liquid when done right. Practice on an old board or something else before taking your act live. Shine
If you want the most versital sander – get the Milwaukee 7068 variable > speed – 0 to 6000 RPM – its about $160 new – it will take you anywhere > you want to go. Sorry – that should be the Milwaukee 6078. Shine