Tips For Using Water Based 2K Polyurethane

[@TritoneChris]

I recognize that beauty you're working on! Love your videos, and I can't wait to hear and feel that beautiful work of art you're creating!

[@HighlineGuitars]

I usually don't put customer builds in my videos because of the haters. But this one is so cool, I couldn't resist. So far no haters, knock on Swamp Ash!

[@TritoneChris]

@@HighlineGuitars Well I'm glad you did, I love seeing it!

[@ceeweedsl]

I think you do a great job of emphasizing how to protect yourself. Isocyanates are considered to be some of the nastiest stuff out there, even with the new lower concentration formulations in the water-based stuff. The next generation ones you refer to use a "cross-linker" instead.

[@HighlineGuitars]

The isocyanate used in Centurion water-based 2k polyurethane is a highly modified version that is nothing like the stuff used in solvent-based 2k polyurethane. I suggest you contact Centurion and ask them about the difference.

[@ceeweedsl]

​@@HighlineGuitars Seem's prudent for anyone using any 2K poly check the product's Safety Data Sheet. I found a good discussion on these water-based 2K urethanes searching for "2k water polyurethane target" and read "what wood finishers should know" In part 1 and part 2 there are good comments from pros who use these water-based ones. Bottom line- just as you say, you really want to use full quality PPE. It sounds like a very bad idea to spray the stuff without good ventilation and an organic vapor filter.

[@HighlineGuitars]

@@ceeweedsl Very true. Of course you should always spray with good ventilation and the proper filter no matter what you're spraying. Claiming isocyantes are "some of the nastiest stuff" ignores the recent advances in their chemistry and amounts to spreading misinformation. Those articles you read were written by Target Coatings, a manufacturer of 1k water-based products. It's a marketing piece and is biased against their competitors who sell 2k water-based polyurethanes.

[@dalgguitars]

Thank you Chris. I'm just getting ready to spray some of this product over the next few days. This has been really helpful!!

[@dougw2340]

Renner is saying with their 2k waterbase, the isocyanates are encapsulated by the product and your current ppe would be fine.

[@RC-xi1xb]

Great tips as always Chris! Thank you for always sharing!

[@tomdowler5416]

You’ve used a lot of different water based finishes over the years. Could you do a video with pros and cons of each?

[@HighlineGuitars]

I might just do that.

[@Wolkearth]

Thank you

[@inourvendetta1]

Can you spray this over Solarez grain sealer Or should I just use z poxy? I also need to fill in termite holes in Burl Maple top Just wondering what the best steps are. Thanks again You have the best videos!!

[@HighlineGuitars]

Yes. You can spray it over Solarez. Use sawdust and superglue to fill the worm holes.

[@inourvendetta1]

@HighlineGuitars Thanks, man. You are literally the best I'm going to buy some of your merch

[@matthewharamis2329]

Chris, great informative video. I was wondering if its possible to use the Centurion catalyst with other brands of 1K such as Varathane, Brite Tone, etc. and if so what is the outcome.

[@HighlineGuitars]

Not that I know of

[@bobfiliczkowski5502]

I’m in a dry hot climate in California and the outdoor temps can vary a lot. In previous videos about water based polyurethane you suggested using retarder. Is a retarder required for this product in order to get a smooth finish?

[@HighlineGuitars]

You have to test to know for sure.

[@randysummers9228]

You mentioned mixing enough for three coats but also said you clean the gun between coats. Are you mixing the three-coat batch in a separate sealable container and then pouring 1/3 of the batch in the gun each spray session? If so, which containers have you had good results with doing this. Also, what volume of product do you mix for three coats? I know it will vary from person to person and one guitar to another but a starting point for experimenting would be much appreciated. Thanks as always for the informative content!

[@HighlineGuitars]

I mix in a plastic cup from the dollar store, pour it into the gun, spray, pour what’s left back into the mixing cup, and clean the gun.

[@perosales30]

Great video tutorial ,what size needle are you using for a 2K poly?

[@HighlineGuitars]

2mm

[@Chemcaster]

Great video, and nice idea about the 10 coats and two coats with different cat. amounts. From my understanding, polyurethane catalyst doesn’t contain isocyanates - they are typically amines which are smelly but much less toxic. There would be no polyurethane without isocyanates because isocyantes react with polyols in the presence of the catalyst to form the urethane polymer.

[@wesleywayne303]

The Centurion 2k cat is #4002 which does have ISO’s, pretty gnarly stuff. Spec sheet on their site.

[@bobfiliczkowski5502]

Can you tint this polyurethane with products like transtint or Colortone stain to create transparent shaders?

[@HighlineGuitars]

Yes, but test!

[@asterisk606]

Great tips!

[@subdrums]

Great info ! I’m thinking I’ll try this for the clear on my next build. I have found that people tend to have slightly different definitions of what one coat is. When you refer to one coat, are you hitting every angle of the item being sprayed once and calling that one coat? Alternatively, do you spray every angle of the item two or three times within a few minutes and call that one coat?

[@HighlineGuitars]

I try to spray one even coat of the entire surface. If I see a dry spot, I'll hit it again so I end up with a uniform wet coat. The alternative you describe works well with nitrocellulose lacquer, but I would do it with a catalyzed polyurethane. You need to spray one even wet coat and let the catalyst do its thing for a couple of hours before you spray the next coat.

[@subdrums]

@@HighlineGuitars thanks for the info! I tend to do the latter of the two scenarios. That makes sense as I’m mostly familiar with nitrocellulose lacquer. I’m new to water based finishing and plan on moving away from nitro for all of the same reasons that you’ve stated before. Unless a customer specifically request nitro. Thanks again for the incredibly helpful information. You’ve become one of my go to sources for guitar related information.

[@Andluth]

Have you done any thickness testing? I always spray a panel with wide tape on it along with the guitar and sand, spray, and buff the same way. pop the tape off and peel the finish off and mic it.

[@HighlineGuitars]

No. I see no reason to.

[@SarcastSempervirens]

Hi Chris! Could you please do a short video on the differences between a stain vs. a dye and the problem of blotchiness on certain woods and how it could be addressed (like sealing first, potential activation of the stain/dye with the coats on top of that..) You do have videos on staining and artist dyes and similar, but it's separate cases and I think many would benefit from having a short clip on precisely this problem people seem to have and can't figure out what goes first and when. Thanks!

[@HighlineGuitars]

The next time I dye or stain a guitar, I will.

[@SarcastSempervirens]

@@HighlineGuitars thanks very much!

[@sivucit]

hi what tip are you using for Qualspray QS-125WB... Also how is this different from automotive clear coat.. thanks for sharing the video

[@HighlineGuitars]

I've gone back to my Earlex 5500 with a 2mm needle for this product. It's too thick for the Qualspray without significant thinning, which I try to avoid for the purpose of time.

[@gregorylibbee1212]

Hi! I've been using this 2K on various jobs in my shop with mixed results (clears & tinted to color). Have you ran into micro bubbles yet? Additionally, are you finding that this coating has voids in it that fill with polishing compound after level sanding and buffing? I love the drying time and hardness of this coating but compared to ilva this is VERY finicky to spray so far. Please share your thoughts. Thank you for the very informative video!

[@HighlineGuitars]

I have never experienced the issues you describe. It has worked brilliantly for me.

[@gregorylibbee1212]

@@HighlineGuitars Thank you for the response. I've been having problems specifically with the white tint base tinted to color. The clear base tinted to color sprayed pretty decent. A little thin for my taste, so I ordered the thickener for better hang. As for the supplied air system you mentioned...I use one all the time. I bought the "Breathe-Cool" turbine. I couldn't recommend it enough. I love your videos and always pickup great tips that translate into my profession. Keep up the great work.

[@inourvendetta1]

After I z poxy my guitar what grit should I use on it before applying 2k clear? Thanks again!

[@HighlineGuitars]

At least 400 grit.

[@inourvendetta1]

@HighlineGuitars Awesome thanks man! I ordered a shirt from you can't wait to wear it.

[@darylburke4575]

Can it be used over acrylic lacquer paint

[@HighlineGuitars]

For specific compatibility questions, please contact the manufacturer.

[@drisiguitars]

Between coats - Should the spray gun be cleaned by spraying water?

[@HighlineGuitars]

I should be disassembled and cleaned.

[@drisiguitars]

@@HighlineGuitars Thank you.

[@r.llynch4124]

Had a visit with them here in Texas since they are about 30 miles from my house. I picked up the gloss. It's now called 2800 series but the gloss is NOT on the website. You have to call them and order the gloss since they do not sell a lot of it. They recommended 15% cat mix but I like your ideal to go 10% and then 20% for the last bit. I have the same gun your using and I'm finding the 1.5 tip @ 29 psi seems to work best. Do you use the 1.5 tip as well? f.y.i..they also sell a black tint colorant specifically for the clear. I do not think that water based dyes will work but I have not tried that yet, have you?

[@HighlineGuitars]

My understanding is the 1800 series is being reformulated due to supply chain issues. Not sure what that will mean for 1800, but I haven't tried the 2800 series yet since I still have a half-gallon of 1800 gloss, a full gallon of flat, and a full gallon of semi-gloss to get through. I haven't tried tinting the 1800 series since I use it only for clear top coating. If I need to spray a tinted clear, I use Crystalac Brite Tone tinted with aniline dye (Keda) and top with 1800 catalyzed. With the 1800 series, I use the 1.5 tip @ 29 psi as well. However, once it is catalyzed, I have to thin it with water as it is too thick to spray. I can spray it without thinning if I use my Earlex 5500 system with a 2mm tip. How are you finding the 2800 gloss looks after spraying it? What's the cure time like?

[@r.llynch4124]

@@HighlineGuitars I have only used it for a black base coat at this point, actually today was my first usage. I will let you know my thoughts once I clear coat. I thought it was a little thick for the Qualspray 125WB .How much water do you use for each 4 oz mix or do you just go by feel? I mixed 4 oz tinted clear plus .67 oz of the hardner.

[@r.llynch4124]

@@HighlineGuitars So I clear coated 2 guitars and its a great product. I mixed 3.5 ounces clear to .35 ounces cat and mixed well then added 2 tsp water for each session. It sprayed so well the level sanding is going to be a breeze. For tinting, Jim @ CIC stated 1 oz for every 16 ounces, add the cat, then water to thin. He also said to mix it super well using a really small paddle and drill when using any tint colorant before using. I also used a heat gun after each coat approx 1 ft away and moved fast to set the clear. I'm very happy with this so thanks for turning me on to it. BTW the 1800 is now 2800 which is what I used.

[@r.llynch4124]

@@HighlineGuitars Also, Jim said do not tint with dyes just use tints from a paint store.

[@HighlineGuitars]

@@r.llynch4124 I'm glad the 2800 is working well for you. As for the 1800, the Director of Sales at Centurion told me it's on a temporary hold while they reformulate it. He told me the 1800 will have more resin, thus giving it higher reactive groups with regards to the hardener, and it will produce an overall better finish. He also told me the 4002 catalyst uses aliphatic isocyanates rather than aromatic isocyanates. Aromatic isocyanates are more dangerous as they create harmful gas. Aliphatic isocyanates cure polyurethane without the danger associated with off gassing.

[@dr66ss396]

What spray gun are you using?

[@HighlineGuitars]

A Qualspray QS-125WB.

[@KendallGuitarWorks]

Centurion's 1800 series water-based 2K polyurethane seems to be discontinued. The link above doesn't work. Do you have a recommendation for an alternative?

[@HighlineGuitars]

No, I don't. I've only used the 1800. They have 2800, but I haven't used it. There is also Renner 2K and Milesi 2K. Both are water-based and they are supposed to be very good as well.

[@KendallGuitarWorks]

@@HighlineGuitars Thanks for the reply. Your video and the comments/replies are a wealth of information.

[@dantahoua]

Does the finished result over Crystalac Brite Tone justify all those "drawbacks" (have to mix catalyst, poison, cannot let it in the gun for a long time) ? I'm curious as I now use Crystalac and love it.

[@HighlineGuitars]

I still like Crystalac, but I need a bullet proof finish for my customers that I can buff out the day after I spray the last coat.

[@gcfxtrader9630]

I can only find satin and flat where do you buy your centurion

[@HighlineGuitars]

Contact them through their website. centurionwoodcoatings.com/

[@luisownerbr]

Cool stuff. Unfortunately water based stuff is not very common where I live, most of these products are marketed towards the hobbyist woodworker or quick and easy repairs.

[@HighlineGuitars]

That's true with most single part (1K) polyurethanes, but 2k polyurethanes are a whole different animal. They are marketed to the high end cabinet and furniture makers. The water-based 2k polyurethanes originated in Italy and are very popular among high end woodworkers in Europe. However, they are not readily available to general consumers.

[@luisownerbr]

@@HighlineGuitars I hope they dominate the market some day. I've been experimenting with some oil based high solids clear in my garage after I decided building guitars a few weeks ago and the atmosphere is pretty much ruined for quite some time after I spray. I know water based products are not exactly healthy as you mentioned in the video, but I guess they don't leave that lingering solvent smell behind.

[@scalylizardplays6067]

What types of paint are compatible with using this as a clear coat?

[@HighlineGuitars]

All I have used is water-based Createx paints. For anything else, you'll have to confirm with the manufacturer.

[@scalylizardplays6067]

​@@HighlineGuitarsHow many colors do those come in?

[@HighlineGuitars]

@@scalylizardplays6067 createxcolors.com/

[@scalylizardplays6067]

​@@HighlineGuitarsCan you blend those colors to make new ones?

[@HighlineGuitars]

@@scalylizardplays6067 Yes

[@eksine]

instead of mixing it all at once just mix what you need for each coat. than you don't have to worry about pot life as much, just add whats left to the new mix. not sure about waterbourne but solvent based clear coat has some with high solids so you could do all of your clear coating in 1 day instead of 4 days. 4 days is way too long , it sounds like your layers are too thin to be adding that many layers on. I know with 2k car paint if someone tried to put that many layers on it would be too thick even with medium solids clear coat.

[@wbaglivio]

Centurion has discontinued the 1800 line stating "supply chain issues are forcing a re-formulation and it may be available again in the future" and are steering people towards their 2800 line, which I believe is a 1k not a 2k product. I'm curious if you have any experience with the 2800 line or what your plans are when you run out of 1800?

[@HighlineGuitars]

2800 is a 2k and works fine.