jay5 Posted April 26, 2005 Report Share Posted April 26, 2005 So, I am looking ahead to the finishing portion of guitar building. I am almost at the point of being fully "tooled up" ($100 a week part time doesnt make for a speedy collection of tools ) so my project should be finished midway through the summer. I am having so much fun just working out templates and jigs that I cant imagine not starting another guitar as soon as this one's finished. Anyway, that brings me to my question(s). I was origionally planning on finishing this guitar with Reranch rattlecan products but after reading some of Jeremy's awesome tutorials I decided that in the long run it would probably be better to bite the bullet and spring for a decent gun and compressor. Going on Jeremy's advice, I found this gun which looks pretty decent. It says that it needs 13 CFM @ 23 PSI. Most of the compressors I have seen rate their CFM output much lower than that but at higher PSI. For instance, this compressor from Porter Cable has a 7.7 SCFM at 40 PSI and 5.5 SCFM at 90 PSI. Would I be wrong to assume that I could get close to 13 @ 23PSI? Does this thing have decent HP as far as compressors go? I guess I am really looking for a little guidance to see if I'm heading in the right direction or not. Any help will be greatly appreciated. Thanks guys! Quote Link to comment Share on other sites More sharing options...
bigdguitars Posted April 26, 2005 Report Share Posted April 26, 2005 go with this gun its a good price runs on almost any compssor thats rated at 15gal http://search.cartserver.com/search/search...keywords=128504 I have a 15 gal compressor, used on ebay for 130, plus this gun paid 150 for it.... Its the best of both worlds. Quote Link to comment Share on other sites More sharing options...
erikbojerik Posted April 26, 2005 Report Share Posted April 26, 2005 Jay, I am also thinking along these lines....but I do know that on the larger compressors that I've worked with in my job, the output pressure (PSI) is generally adjustable. Of course, the ouput (CFM) will drop when this happens...these things should come with a graph of PSI vs CFM. I think this could be figured out from the formula for Pouiselle flow <--college physics textbook Quote Link to comment Share on other sites More sharing options...
Grindell Posted April 26, 2005 Report Share Posted April 26, 2005 I just bought an Astro touch up gun from Amazon for $35, and it is a good deal. Plus, it is the preferred gun by Yas, the guy from the Fender Custom Shop who finally figured out how they did the 2 and 3 tone sunbursts at Fender. Or so the claim for all this goes from the Stew-Mac video. Quote Link to comment Share on other sites More sharing options...
jay5 Posted April 27, 2005 Author Report Share Posted April 27, 2005 Wow, 15 gal. Hmmm... I dont know if I really have the space for a 15 gal. compressor. Shipping on that must have been cheap I would hope you could run any gun on a 15 gal! Erik, youre so right. I really wish I could find a comparison of CFM and PSI. Quote Link to comment Share on other sites More sharing options...
Drak Posted April 27, 2005 Report Share Posted April 27, 2005 I've had the same homemade rig ever since I put it together about 9 years ago. BBQ Propane gas tank, some brass fittings, PSI gauge, Campbell-Hausfeld line dryers on both sides of the tank, a Home Depot pint gun, and a Speedaire 3/4 HP compressor. Homemade, probably very dangerous if taken above 125PSI (but I never take it above 60-70PSI and I'm still using the same propane tank 9 years later) All this CFM/PSI/FPS stuff is sort of just conversation talk to me. I just bought the stuff, slapped it together, and now use it all the time for 9 years, and have created some things that make me very happy with it. It has worked for me so well I've never considered buying anything else, I've shot every single guitar I ever built with this rig...but I'm not really recommending anyone else go this route either. . it's just what I patched together those years ago and it's still working fine for me, and it's portable and easy to store. Those are paramount conditions for me, I don't want or need any huge/heavy/bulky/fancy compressors/holding tanks/etc. Personally, I think the brains, talent, creativity, imagination, and the experience ~behind~ the gun mean far far more than the kind of gun/tank/bling bling you buy. It's not how big or fancy your tool is, it's what you can DO with it that counts. What I'm saying is this: You could spend 3 months looking over data about what's the proper ehhhh, 'kit' (love that English slang) to buy, and another guy who just went out and bought the danged thing has been actually shooting on his kit for 3 months and has already learned lots of good stuff, like how to keep his guns clean and break them down, how to mix colors and what happens when you do, the sheer magic of owning pipettes and glass baby food jars, what the proper mixture is so he doesn't get sagging/runs or dry/powder finishes, the types of dyes/finishes he prefers to work with...you gettin' my drift? Quote Link to comment Share on other sites More sharing options...
RAI6 Posted April 27, 2005 Report Share Posted April 27, 2005 It's not how big or fancy your tool is, it's what you can DO with it that counts. That's what I've been trying to tell my wife for all these years..... Quote Link to comment Share on other sites More sharing options...
jay5 Posted April 27, 2005 Author Report Share Posted April 27, 2005 Drak, I totally agree with your sentiments, I just figured that having good "kit" would make it that much easier on myself. What is the propane tank for? Like a reservoir? So I have been looking on ebay at some compressors (some great deals suprisingly) and even some of the larger HP models with larger tanks (upwards of 30 gallons) still only have a CFM rating of 8.6. So like Drak said, is the CFM thing a somewhat pointless figure? I remember Jeremy saying that for the short time you are actually spraying on a guitar a small compressor should be fine. Do what specs would be ideal for the gun I noted (or the SATA that BigD recomended)? Quote Link to comment Share on other sites More sharing options...
Shamrock Posted April 27, 2005 Report Share Posted April 27, 2005 (edited) I actually use a self contained HVLP (High Volume/Low Pressure) unit that I got from Harbor Freight for $79.99. It sprays nice even coats with very little overspray and therefore, very little wasted lacquer. Does a very nice job and leaves very little mess. My shop is pretty small ( a 10' X 14' shed ) and I just use a box fan in the window set on high speed to exhaust the fumes and It works great. Just my 3.785 cents (after interest and penalties) Edited April 27, 2005 by Shamrock Quote Link to comment Share on other sites More sharing options...
erikbojerik Posted April 27, 2005 Report Share Posted April 27, 2005 Drak, your 3/4 HP compressor motor does not have an integrated tank, I take it? Or do you have two tanks for some reason? Quote Link to comment Share on other sites More sharing options...
mledbetter Posted April 27, 2005 Report Share Posted April 27, 2005 There is a 1.5 hp tankless compressor on ebay with a buy it now for 129 bucks.. Come to think of it, i've seen these before.. That's pretty smart. A propane can would hold a lot of air. Quote Link to comment Share on other sites More sharing options...
Drak Posted April 27, 2005 Report Share Posted April 27, 2005 Yes, you're both correct, my Speedaire is just a compressor only, and the propane tank is my holding tank reservoir. Quote Link to comment Share on other sites More sharing options...
jay5 Posted April 28, 2005 Author Report Share Posted April 28, 2005 So is the consensus that the two specific products I listed will work together? Quote Link to comment Share on other sites More sharing options...
jay5 Posted April 30, 2005 Author Report Share Posted April 30, 2005 Anyone? Beuler? Beuler? Quote Link to comment Share on other sites More sharing options...
donald k wilson Posted April 30, 2005 Report Share Posted April 30, 2005 Hey Jay5, CFM is flow of air at the point being measured. PSI is the pressure of air in the tank, gal is the volume of air at given pressure. Increasing cfm at the gun or psi at the gun (more material and or bigger fan pattern) will reduce your volume faster in the tank. a bigger tank takes longer to drain but also longer to fill Cycle time of the motor running the pump is important, compressors running longer get hotter. (smaller pump, larger tank) This leads to condensation in the tank when the air cools down and moisture contamination in the spray. there are filters for this. You dont want to run out of air in the middle of a spray job and have to wait for the recharge, you lose the working edge and will have problems. All other things being pushed aside, (cost,space...) more air is better. I have used hvlp for several years now and love it. the little turbine systems are really handy. blah blah blah sorry, hope this helps, spraying is pretty fun dkw. Quote Link to comment Share on other sites More sharing options...
jay5 Posted April 30, 2005 Author Report Share Posted April 30, 2005 Thanks Donald! Quote Link to comment Share on other sites More sharing options...
Devon Headen Posted April 30, 2005 Report Share Posted April 30, 2005 This leads to condensation in the tank when the air cools down and moisture contamination in the spray. there are filters for this.← I think everyone needs a moisture trap/filter on their air line anyway. There's nothing quite so annoying. Especially when you're at the very end of a coat, and you discover water in your lacquer. Quote Link to comment Share on other sites More sharing options...
erikbojerik Posted April 30, 2005 Report Share Posted April 30, 2005 So does this mean those little 5 gallon compressors (on sale with nail guns) you see at Home Depot are too small? Drak's propane tank can't be more than about 5 gallons....how would that work? Just shoot a coat short enough that the tank won't peter out, before the motor cycles on again? Quote Link to comment Share on other sites More sharing options...
jay5 Posted May 1, 2005 Author Report Share Posted May 1, 2005 Thats kind of what i was wondering myself Erik. I dont think i would go as small as one of those pankake compressors but I was thinking something along the lines of the porter cable one I linked to in my original message would be ok, but Im not really sure at this point. I imagine that it would have enough capacity to allow for an adequet spraying time but Im still somewhat confused as to whether exact CFM output (in relation to your specific gun) is essential or not. That gun that I linked says it needs 13 CFM @23 PSI but I'm not sure if that compressor will be able to make quite that. I'm still a bit perplexed at this point. Quote Link to comment Share on other sites More sharing options...
donald k wilson Posted May 1, 2005 Report Share Posted May 1, 2005 Different guns will will have different air consumption. A siphon gun draws from the bottom through a venturi created in the head and requires higher cfm and psi just to get the material out of the cup. not recommended for higher viscosity materials. Gravity feed guns have top cups and don't need as much air to get things going. high vis. materials require higher psi and cfm for atomization (spray quality). HVLP guns accomplish this with significantly lower psi but much higher cfm. Atomization is caused by higher vol of air through the tip and many more ports for the material to flow through. Turbine is for air flow, pump is for psi. Regardless of gun style or air source in order to spray well you must move air. Atomization is a "violent" reaction of a static material being introduced to a dynamic force. different materials react better or worse to different systems and there are always tradeoffs. Have I thoroughly confused the issues now... If you are planning on spraying just laquers and small jobs a conventional gun and smaller compressor would probably be fine, you can move enough low vis material If you want to spray high solids catalyzed or wb urethanes or bigger jobs you will need something larger. We spray professionally, I use a Sharpe gravity feed hvlp gun, different tips for dirrerent materials, with a 5 hp 60 gal compressor, (generic cfm ratings for that size) and we can spray all day. With this type of gun and something in the 3 hp 30 gal range you should be able to spray most anything on smaller jobs.. I've been spraying for almost 30 years and I'm still learning. Maybe I'm thick headed Quote Link to comment Share on other sites More sharing options...
Shamrock Posted May 3, 2005 Report Share Posted May 3, 2005 Wow, I never thought I'd get a science lesson here. But it does help understand the process a little better. Thanks, Don Quote Link to comment Share on other sites More sharing options...
donald k wilson Posted May 3, 2005 Report Share Posted May 3, 2005 That was a little over the top wasn't it... Don't mean to sound like a lecture, I 've made lots of mistakes, wrong combinations of everything... just trying to throw some helpful info out there. There are people doing really nice work with spray cans and brushes, it's all ultimately in how you make it work. thanks for your patience...dkw Quote Link to comment Share on other sites More sharing options...
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