Freddie Posted July 6, 2014 Report Share Posted July 6, 2014 So, I've been working on four radiator covers for a customer. He picked a design from my portfolio, which is slatted with 3/4"x3/4" slats. Great! So, to keep thing low cost like the original I built, I am using mdf for the slats. The first cover I did was shot in cab acrylic lacquer, and I had no issues. The current project is a more budget friendly approach with latex paint. I opted to pre finish the slats so I could build up and smooth out the fuzzy sides of the mdf. Well, wouldn't ya know, the slats all curled up on me. As frustrated as one can be, I wanted to let them sit and see if they would spring back. Nope. I assume this is due to the latex causing this reaction to these thin slats. Like I said, with the solvent based application I had no issues to the same size materials. I attached a picture of the original cover, and the in progress cover. I don't remember the dimensions of the old cover, but the new one is 5' wide by 3' tall. It needs 31 slats for this one cover, and 99 total for all 4 covers. Has anyone ever had this issue? Fun times, I'm gonna take tomorrow off and drink some beers and I'll come back to it monday. Quote Link to comment Share on other sites More sharing options...
..Kev Posted July 6, 2014 Report Share Posted July 6, 2014 Is it too late to switch material Freddie? I'll be the first to admit that I haven't done much with MDF especially finishes.. Quote Link to comment Share on other sites More sharing options...
Trip Posted July 6, 2014 Report Share Posted July 6, 2014 To summarize: long/thin/narrow MDF component (approx 3/4x3/4x32"). Shoot solvent-base is fine, shoot WB and they warp... Fair summary? You know, as cantankerous as Don could sometimes be, I really wish he was around for stuff like this -- he'd just know the answer... He'd just know... Don, come back we miss you... I'm assuming this is repeatable and not a one-off where specific environmental conditions may be a factor? Sorry, I don't use MDF all that often... Mostly sandwich material for veneer... Shoot a shellac seal-coat? Sorry, it's a bit of a guess... Note: I'm overly enamored with shellac, so tends to be my answer for everything Quote Link to comment Share on other sites More sharing options...
Freddie Posted July 6, 2014 Author Report Share Posted July 6, 2014 Is it too late to switch material Freddie? I'll be the first to admit that I haven't done much with MDF especially finishes.. Tiods, the cost offset of switching would be astronomical! Price is set, unless I up it, which is never a good call to make. I know I can't spray this project, its just not in the budget for this one. Maybe an oil based primer to seal the mdf. Quote Link to comment Share on other sites More sharing options...
..Kev Posted July 6, 2014 Report Share Posted July 6, 2014 Sounds like some testing is in order.. Wish I had better answers for you bud! TripH is correct in that Don would have the answers.. Quote Link to comment Share on other sites More sharing options...
Freddie Posted July 6, 2014 Author Report Share Posted July 6, 2014 To put this into perspective for you guys, they gave me four 1x6x8 pine boards to use on this project. I f#^%$n hate pine, and I told them the grain would telegraph through the finish. They said thats fine. So, my thought is they just want me to perform magic with pine and a paint brush. 1 Quote Link to comment Share on other sites More sharing options...
Trip Posted July 6, 2014 Report Share Posted July 6, 2014 ==>I know I can't spray this project I must be missing something... Sorry for being obtuse, but the left photo look like a spray job... No? Quote Link to comment Share on other sites More sharing options...
Freddie Posted July 6, 2014 Author Report Share Posted July 6, 2014 ==>I know I can't spray this project I must be missing something... Sorry for being obtuse, but the left photo look like a spray job... No? Yes, and that cover sold for $600. My current project doesn't have the budget for me to do that. Quote Link to comment Share on other sites More sharing options...
Trip Posted July 6, 2014 Report Share Posted July 6, 2014 ==>My current project doesn't have the budget for me to do that.. I'm sorry, I'm missing something... Again, I must be obtuse... Do you have spray gear? And you can't shoot a seal-coat of something like shellac? Again, it's after midnight and I'm watching Law&Order UK, so the distraction level is high... Apologies... Quote Link to comment Share on other sites More sharing options...
Freddie Posted July 6, 2014 Author Report Share Posted July 6, 2014 ==>My current project doesn't have the budget for me to do that.. I'm sorry, I'm missing something... Again, I must be obtuse... Do you have spray gear? And you can't shoot a seal-coat of something like shellac? Again, it's after midnight and I'm watching Law&Order UK, so the distraction level is high... Apologies... Lol, all good trip. Here is the skinny: I have spray guns that I use in the spray booth at my boss's auto shop. I cannot spray in my own shop since I have a pregnant sister inside the house. I don't like to just show up to my boss's shop to work on personal projects, so what I usually do is charge the customer $100 bucks to run the booth(costs a lot to run that thing). Shellac is cheap and available locally, might give it a go. Quote Link to comment Share on other sites More sharing options...
Trip Posted July 6, 2014 Report Share Posted July 6, 2014 Ahhh, now I get it... You can brush shellac... Done it a few times... Works fine, just not as fast... Quote Link to comment Share on other sites More sharing options...
wdwerker Posted July 6, 2014 Report Share Posted July 6, 2014 I don't love MDF but your application makes good sense. BIN primer is white pigmented shellac. I have used it for a few decades. Great at sealing over stains and priming in general. Dries fast even when brushed. Sands well to take down the MDF fuzz and it's usually not too expensive. Made by Zinnzer I think If it was me I would grab a quart, prime and paint a few strips and see what kind of results I got before I tackled 99 pieces for the second time. By using a white primer you can use thinner coats of latex which might help with any moisture problems. Another approach would be to use better MDF, there are higher density boards with more resin in them and moisture resistant varieties as well. 1 Quote Link to comment Share on other sites More sharing options...
wdwerker Posted July 6, 2014 Report Share Posted July 6, 2014 Posts like this are why I like to hang out here. You can tap into several views of how to fix an issue. Great give and take of knowledge! 1 Quote Link to comment Share on other sites More sharing options...
DaveT Posted July 6, 2014 Report Share Posted July 6, 2014 Water down some PVA glue and seal the MDF with it. Quote Link to comment Share on other sites More sharing options...
Freddie Posted July 6, 2014 Author Report Share Posted July 6, 2014 Water down some PVA glue and seal the MDF with it. DaveT, I am a bit nervous since the mdc slats are so narrow at 3/4x3/4, the water glue will persuade them to start bending. I have used this method on raised panels with great success, but this current application has me overly cautious now. Quote Link to comment Share on other sites More sharing options...
Tpt life Posted July 6, 2014 Report Share Posted July 6, 2014 If moisture will cause thin MDF to curl then I would be hesitant to brush shellac now that rattle cans of shellac are available. Quote Link to comment Share on other sites More sharing options...
rodger. Posted July 6, 2014 Report Share Posted July 6, 2014 A while ago I did a large, walk in closet built-in out of MDF, for the same budget reasons you provided above. The client didn't want to opt for the slighter higher cost of a decent paint grade ply. Anyway, I needed some thin strips so I could scribe the wall and hide a gap due to uneven drywall. The strips were cut and primed, and they curled pretty bad. So I redid the strips, nailed them on, then primed and painted them after install. Solved the issue for me, but not sure if it's an option for you. Quote Link to comment Share on other sites More sharing options...
wdwerker Posted July 6, 2014 Report Share Posted July 6, 2014 Not sure how available poplar is on Long Island but it's pretty cheap around here. I would have built the whole thing out of poplar.it paints very well. Sometimes low budget customers are just trying to get more bang for the buck at your expense. 2 Quote Link to comment Share on other sites More sharing options...
Trip Posted July 6, 2014 Report Share Posted July 6, 2014 ==>poplar is on Long Island but it's pretty cheap around here Poplar is pretty cheap in NJ. And you're spot-on -- Poplar paints beautifully... Not exactly sure what property Poplar has that lends itself to paint, but for some reason, it's one of the few things I can paint and not make a pig's eye out of... Quote Link to comment Share on other sites More sharing options...
wdwerker Posted July 6, 2014 Report Share Posted July 6, 2014 I use soft maple for paint grade raised panel doors because it is harder and doors get a lot of use & wear. But other than a situation like that poplar is the way I would go. Quote Link to comment Share on other sites More sharing options...
Freddie Posted July 6, 2014 Author Report Share Posted July 6, 2014 Thanks guys! Yes, poplar is very popular among paint grade application, and is one of the top candidates for this type of stuff along with interior trim work. I have used soft maple for that same reason that it is more durable and not as prone to denting and fiber crushing. I had called my lumber supplier this past week to get a bf price of poplar, but they were closed this week for the holiday. If I can get it at a reasonable price, it may be the solution for my dilemma, but for that many slats it will require a decent amount of poplar. I am taking the day off from it today since it's my sisters baby shower. We are having a big guys and girls party at the house, so I will unwind for the day, then go back to being frustrated with this problem tomorrow. Quote Link to comment Share on other sites More sharing options...
G S Haydon Posted July 6, 2014 Report Share Posted July 6, 2014 WB is the issue on these thin bits. It's made it badly balanced. Even MDF bows with moisture changes. Pick a spirit based primer for these times. If you wan to use solid I would have a piece of wood as thick as one of the slats are wide. I would finish plane the edge, rip off a slat, plane the big bit and rip another slat. I would not worry that the unseed face is sawn. Quote Link to comment Share on other sites More sharing options...
DaveT Posted July 7, 2014 Report Share Posted July 7, 2014 DaveT, I am a bit nervous since the mdc slats are so narrow at 3/4x3/4, the water glue will persuade them to start bending. I have used this method on raised panels with great success, but this current application has me overly cautious now. I sealed some 12mm MDF with this method a few months ago. Instead of the normal 50/50 mix I made it 75/25 PVA/water as these boards were going to be outside. No problems with curling/bending. Some other ideas that I've heard of are BLO (makes the surface hard and slick) and epoxy diluted with alcohol (again, makes the surface hard) although I haven't tried either myself. Quote Link to comment Share on other sites More sharing options...
Coop Posted July 8, 2014 Report Share Posted July 8, 2014 Freddie,I hate to ask this and since no one else has, I'm assuming I'm the only dumb one. What is a radiator cover? Quote Link to comment Share on other sites More sharing options...
Tpt life Posted July 8, 2014 Report Share Posted July 8, 2014 https://www.google.com/search?q=steam+house+radiator&client=safari&hl=en&source=lnms&tbm=isch&sa=X&ei=Lfy7U9aiBs6myATD4oLgCg&ved=0CAgQ_AUoAg&biw=320&bih=372#facrc=_ Behold the home heat steam radiant heat device (radiator.)https://www.google.com/search?q=radiator+covers&client=safari&hl=en&source=lnms&tbm=isch&sa=X&ei=0vy7U6aLCsGiyASvjYD4Cg&ved=0CAgQ_AUoAg&biw=320&bih=372 And then some images of covers. Quote Link to comment Share on other sites More sharing options...
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