Check out this video - Scale Model Body Modification Without Filler or Glue

[Dpate]

This is super dope.  He makes it look so easy, but this may be a new skill to learn in the hobby.

 

[ChrisBcritter]

Very interesting technique! I wouldn't use it on A-pillars, but I can see it for installing Styline front and rear ends.

[Exotics_Builder]

Would definitely want a good air current across the workspace and probably a mask.  Vapors from that would not be healthy.  I have a tool with multiple tips including something that is like a Number 11 Xacto blade to use in working plastic.  That stank when used and seemed hotter than the 97 degrees he referenced.  Need to dig it out when back from our trip

 

[peteski]

Polystyrene melting point is ~ 240 °C (464 °F).  Not everythign we see on the Interwebs is true and accurate.

[Ace-Garageguy]

A worthwhile technique to add to the bag of tricks, but a little common sense needs to be employed.

The 97-degree reference is idiocy. Think about it.

Pete's right.   (Post immediately above ^^^)

If plastic melted enough to fuse at 97 degrees F, all your models would turn to puddles on a hot day.

The actual melting point of polystyrene, where it will flow or fuse, is 170-280 C, about 340-540 F  (depending on the specific makeup of the plastic).

But don't take my word for it.  https://www.rydtooling.com/plastic-melting-temperature-chart/

This is hot enough to cause bad burns instantly and/or painful blistering if you're not very careful.

It is definitely a skill worth developing, and something very similar is used in the real-car body-biz for repairing plastic components.

But just as with any technique, it will take some effort and practice to master, and it's not a magic replacement for other proven methods.

[Plowboy]

I tried that technique many years ago. It's OK if you have a completely clean bench that the the cord can't get tangled into. I don't. You also need a safe holder for your heat tool or you'll bump your arm or hand into it and get a nice burn. That was what made me give it up. I'll stick with Tamiya Extra Thin, Crazy Glue and Tamiya putty. 

[espo]

I like this tutorial on the use of a "Wood Burner". I'll be trying this myself at some time in the future based on what I have seen here. As an aside, I remember building the AMT '62 Bel Air hardtop when it first came out. I built the kit as a version of the #4 car driven by Rex White. As mentioned, the wheel wells needed to be flared a little. Not to the extent of the Charger in the film, but just a slight bulge around the stock wheel well openings.  Like the described technique I used my fingers and thumb to shape the plastic body. I was trying to spread the heat over a wide area in hopes of getting a uniform bulge in the fender. My heat source was a light bulb in a table lamp. I do not recommend this technique. While I accomplished the effect I was after it was done at the expense of the feeling in my thumb and fingertips. They were both very tender for some time after. 

[Draggon]

55 minutes ago, Plowboy said:

I tried that technique many years ago. 

I did too, when I was about 14. I was definitely not as gentle or patient as that guy. It did get the job done, but tube glue and bondo seemed a whole lot easier. 

[cobraman]

I know I would ruin a good body. I will stick to glue and putty.

[Ace-Garageguy]

Just a thought...an old-school soldering iron made for lead-based solders runs at around 370 degrees F; it's very easy to convert the tip, or make a dedicated one, to function as shown.

And you can learn to or practice fabricating things from brass with the same basic tool. 

Note that wood-burning tools can supposedly run as hot as 800 deg. F, so some careful research is necessary in selecting and setting up tools like this. 

EDIT: This one has a number of shaped tips, and a temperature controller that should make it useful for a variety of precision soldering jobs as well as the plastic fusing technique in the video.

https://www.mmnewman.com/blog/wood-burning-tool-tips/

Edited May 4, 2022 by Ace-Garageguy

[Mattilacken]

Nice! Might be something for me. Wil look up if I have the right tool

[Plowboy]

2 hours ago, Ace-Garageguy said:

Just a thought...an old-school soldering iron made for lead-based solders runs at around 370 degrees F; it's very easy to convert the tip, or make a dedicated one, to function as shown.

And you can learn to or practice fabricating things from brass with the same basic tool. 

Note that wood-burning tools can supposedly run as hot as 800 deg. F, so some careful research is necessary in selecting and setting up tools like this. 

EDIT: This one has a number of shaped tips, and a temperature controller that should make it useful for a variety of precision soldering jobs as well as the plastic fusing technique in the video.

https://www.mmnewman.com/blog/wood-burning-tool-tips/

A soldering iron was what I used. I had chisel like tip that I could run through the joint. I had a flat tip to do the fill work. It does work. But, it just wasn't for me.

[keyser]

I used batt op surgical cauteries. Do a case, they still had juice, brought them home. Fine wire, I did mostly out of site fusing on panel work, opening odd areas. Not wonderful, burnt styrene not good for lungs. Crude but useful. Wire let you start a cut, then switch to saw or whatever. Glues easier and cheaper in long run

[Dpate]

9 hours ago, Plowboy said:

I tried that technique many years ago. It's OK if you have a completely clean bench that the the cord can't get tangled into. I don't. You also need a safe holder for your heat tool or you'll bump your arm or hand into it and get a nice burn. That was what made me give it up. I'll stick with Tamiya Extra Thin, Crazy Glue and Tamiya putty. 

Sprue goo would work good too.  I would def practice on a salvage kit before attempting on a good kit.  

[Vince Nemanic]

If you have ever seen a technique demonstration at a model show, you know that the spectators move closer to the presenter as the demonstration progresses. 

Many years ago, the late Bob Paeth did a demonstration of sprue soldering at GSL. The smell was so awful that the spectators moved away from Bob. At one point, Bob (a fire fighter before he worked at Revell) aet the sprue on fire, and calmly stood there holding the burning plastic before he blew it out like a match. I think many in attendance thought like me that there was no way we were going to stink our homes up like that.

A friend of mine uses this technique a lot and told me he only does it in his garage and he has a "big fan" venting outside his garage and sprue welds directly in front of the fan. I have never been to his house so I can't describe the set up better. The impression I got is that he has a room fan with a hole cut in one of the exterior walls of his garage. This is something you can do in warm Santa Rosa, California that you can't do where you get snow.

[Brian Austin]

One of the old model-building books discussed using a hot knife to cut out doors, etc.

[Mark]

Tools using heat, probably modified soldering irons or something similar, were used to assemble promo models.  If you have ever taken an old promo apart, you'd see the interior bucket attached by heating the end of the mounting posts and mushrooming them over.  The kits instead had plastic rings that slipped over the posts.

Often the small parts like taillight lenses would have super long pins on the back side.  Those would go through a hole in the chrome bezel, then through a hole in the body, and likewise get heated and folded over on the inside of the body.

[Ace-Garageguy]

On 5/5/2022 at 11:08 PM, Brian Austin said:

One of the old model-building books discussed using a hot knife to cut out doors, etc.

Yeah...and those of us who actually tried it were very disappointed.

Though it seemed like it might be the hot setup, the kerf from the blade was so wide as to make the parts all but useless for any kind of quality build...unless you had two kits and could cut next to the panel lines.

I've experimented with using nichrome hot-wire, as used for shaping foam on some full-scale kitplanes, and again, the cut line is simply too wide.

WARNING: Hot-wire is routinely used to cut styrene-based foams, but DO NOT TRY TO CUT URETHANE FOAM: THE FUMES ARE HIGHLY TOXIC.

[Mr. Metallic]

On 5/4/2022 at 3:01 PM, keyser said:

I used batt op surgical cauteries. Do a case, they still had juice, brought them home. Fine wire, I did mostly out of site fusing on panel work, opening odd areas. Not wonderful, burnt styrene not good for lungs. Crude but useful. Wire let you start a cut, then switch to saw or whatever. Glues easier and cheaper in long run

I use a medical cauterizing tool to remove parts off a sprue when the part is too close to the runner to get my pliers in there. Especially with 60's tooled Revell kits. 

[Scott Colmer]

When I went to my first NNL West I had a chance to talk to Mark Townsend about his models. One of the techniques he shared with me was bonding shapes (plastic fenders, etc.) by crosshatching the backside with a soldering iron. I used it once, on a custom 51 Chevy and it worked OK. I think its time to try again.

[goldfinger]

On 5/5/2022 at 11:08 PM, Brian Austin said:

One of the old model-building books discussed using a hot knife to cut out doors, etc.

I think that was by Dale King. He built beautiful models but some of the info in that book was not what we would do today.

[goldfinger]

When I saw this video it made me think of repairing plastic bumpers using a plastic welder. I remember buying that hot knife from Autoworld and being disappointed with it. However after seeing this i had a woodburning set so i dug it out and tried it on a junk body. It worked okay but a temperature control would help, I think mine was a little hot. However i could see it working well with a little practice .

Edited May 19, 2022 by goldfinger
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