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Building Tips and technical articles. => Building techniques => Topic started by: Paul Taylor on August 15, 2011, 01:00:32 PM
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When sanding off a filler coat of the Randy Smith type..... do you wet or dry sand?
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Paul,
I don't use wet or dry for this sanding. I use some silicon/garnet based sandpaper from Norton called Sandblaster. 320 or 400 grit. It doesn't load up. Just flick it with your finger and everything falls off. You can use the wet or dry stuff, but you will go through a lot of it since it loads up almost immediately.
Forgot, use the Sandblaster dry.
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Just a point of reference, when wet sanding vs dry sanding, dry sanding with 320 is equivilant to wet sanding with 400. The dry sanding makes smaller scratches because of the dry sluff while you are sanding.
I prefer to sand my planes with dry , I always get kinda edgy slathering water onto a wood airplane. Especially if your primer/surfacer is laquer based. It tends to be more absorbant of water than do catalyzed primers.
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I use 320 on a flat sanding block initially then switch to 400 for the final strokes....and plz do a Bob Hunt hint...sand
in one direction only for the smoothest surface.
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I use wet and dry paper and wet sand - but now Randy has mentioned a different paper - I might give that a go - because wet n dry sure loads up if you sand dry!!!!!
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Wynn,
I've tried a bunch of stuff over time. I've tried half the stuff in the Klingspor catalog. Without a doubt, the Norton Sandblaster paper is the easiest. It's takes less pressure, cuts more easily and gives a decent surface. Usually, I sand it down close with 320 then finish up with 400 or 600. Shoot a coat of very thinned clear and use 0000 steel wool to finish. Then clean real well with PrepSol or equivalent (some steel wools have oil in them) and start shooting color coats.
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wonder if I can find that paper down here in NZ ......
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Hey Wynn
If not order some and ship it to me and I'll put it in the box with Bryce's reels. y1
I have been doing a little of both with 600. Smooth as glass but I went a little too far on a few spots. Will have to spot shoot a few places. HB~>
More weight.
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randy - is it Norton or 3M Sandblaster ???
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Hi Randy,
Thanks for the heads up on the Sandblaster paper. I will have to order some! It is very true, wet or dry really loads up when used dry...... bummer!
I have some "gold" sandpaper that doesn't load/clog up much at all, need to see what brand/type it is.
Big Bear
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Wynn,
Sorry, I should have said. Could be listed as 3M or Norton. I have some that say Norton on the back and some 3M. The 3M stuff is called Sandblaster. The Norton stuff (now that I look at it) is called Silicon Garnet Oxide. Same stuff. Sorry about that.
Norton also has some stuff called Silicon Carbide that works pretty well. A bit less cut but wears out more quickly. Leaves a nice surface, though.
Bill,
It's gold colored. It's a silicon/garnet composite.
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Wynn,
Sorry, I should have said. Could be listed as 3M or Norton. I have some that say Norton on the back and some 3M. The 3M stuff is called Sandblaster. The Norton stuff (now that I look at it) is called Silicon Garnet Oxide. Same stuff. Sorry about that.
Norton also has some stuff called Silicon Carbide that works pretty well. A bit less cut but wears out more quickly. Leaves a nice surface, though.
Bill,
It's gold colored. It's a silicon/garnet composite.
Thanks, Randy. I cannot remember where I bought it but I will be looking for it as soon as I am able to get out and about.
Bill
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For sanding before clear coat, I plan on using some 1200 wet. Anyone tried this?
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Hey Paul,
If you get to the point to where you need to wet sand a color coat get some really good quality wet/dry paper from ColorMatch in Memphis. Try 400, 600 and even 1200 grit. Don't use water. Get a spray bottle of Windex and go easy with the spraying. Work a small area at a time and go one direction only. You will find that the Windex helps lift the residue off of the surface and wipe away with paper towels, lots of paper towels.
It will also work with clear coats too.
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I need to sand down the masking tape lines, so I'll try the Windex trick.
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While on the subject, whatever happened to 3M Tri-M-Ite?
W.
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On the subject of sanding in only one direction. Do you mean to set the paper down , move forward , then lift and repeat or just move the sanding block back and forth in same line of movement after contact with surface?
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Thanks for the info about using Windex. It worked like a champ and will start shooting clear tomorrow. Windex is a magic cleaner, I've used to clean and polish chrome, remove oil residue and the list is endless.
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I read a painting article a while back, but I can't remember where or by who, that recommended using Windex for the final cleaning before painting in place of Prep-Sol. The article was by one of the more respected builders and I hate not being able to attribute it to the right person.
Again I think the key is to not get carried away with the Windex spraying and a gentle wipe down with a tack rag to remove any fuzz.
Someone correct me if I am wrong, but I think the idea behind sanding in one direction is to eliminate the natural rocking motion one gets when sanding back and forth.
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For sanding before clear coat, I plan on using some 1200 wet. Anyone tried this?
Hi Larry,
Use the 1200 then 2000 wet when sanding the clear. Then rub it out with a good compound and wax. I have gone as low as 800 when starting on the clear but you have to be careful and use a light hand. Stop sanding immediately if color starts to show in the "Windex". Hit with some more clear and then carry on.
Big Bear
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Kelly,I believe the article in question may have been the one written by Phil Granderson in Model Aviation a couple years back?
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Kelly,I believe the article in question may have been the one written by Phil Granderson in Model Aviation a couple years back?
That's the one. An earlier version was published in Stunt News. Phil wrote it, but it was attributed there to somebody else. I used Windex to prepare the surface for the Isocyanate Death Paint that PTG recommended in the article. It works a treat.