Pre-building

[Sidney Schwartz]

This is something I've been wanting to look into for a while, and the last kit I tried brought the need home. What do you do to "pre-build" a kit to make sure things fit, and to fix things if they don't fit, before painting and assembling? I've seen reference to dry fitting, and also to using something like white glue for a temporary assembly. Bestow upon my your collective wisdom. ?

[StevenGuthmiller]

Pre-planning is especially important if you’re doing a lot of modification on a kit, and the engineering involved requires a large amount of test fitting and mock-up.

I can spend literally months working on a project without ever applying an ounce of paint.

But, in the end, I have learned so much more about model building by deviating from the instructions than I ever would have by being content to build them out of the box.

For me I’ve gotten to the point where it has become nearly impossible for me to answer your question.

It’s just an automatic part of the building process.

 

 

 

 

Steve

[OldNYJim]

For ‘dry assembly’ I like three techniques in particular.

One, is pinning.  Drill a hole in a hidden spot on one part, and insert a little piece of wire.  Then drill a hole where it goes and you’ve got a good repeatable method for mocking up a part repeatably every time.

Second, when that’s not possible or desirable, is this stuff:

Plenty strong enough to temporarily mocking up most parts, and cleans off with water.  Downside is wait time for it to dry, and it’s not so good on big heavy parts (think heavy resin tires, for example)

Third, is this stuff:

It’s an infinitely reusable putty-goo-stuff that you can mold into whatever shape you need to hold things in place, and cleans right off most surfaces just fine.

Also useful can be little jigs and stands to hold things off your bench so you can work on them a little easier - I just scratchbuilt these this week to hold up the (painted) frame of a build so it didn’t get marked up accidentally:

A lot of guys are enjoying using magnets lately too, but I haven’t got a bunch of person experience of using those on my builds so far…

[1972coronet]

After purchasing pre-sale tickets, and receiving notification that I'm prequalified for preapproval, I pre-heat the oven. 

Then I look at my next project and start assembling the rascal in the present-tense.

[dragstk]

I always "pre build". Ive ruined so many models in the past, by finding out, after their painted and the glue is on, it doesnt fit. It seems like it takes longer to fit everything up, but in the end, when your doing final assembly there are far fewer surprises

[Straightliner59]

The absolute best way, is to drill and pin everything--at least when scratchbuilding. That makes every assembly repeatable. Otherwise, the Alene's Tacky Glue Jim showed above is what I use--and a lot of other builders, too!

[R. Thorne]

I started using the Mig brush (and cement) a few years ago because of its pin point precision compared to Tamiya’s flooding.  It allows a tiny amount of cement to be applied for a temporary bond without waiting for drying (my impatience is showing).  Otherwise, CabDriver’s suggestions are dead on.

[Andrew McD]

Is there a trick or technique to aligning parts for pinning?  How do you get a hole located that will line up correctly with the piece that has the pin?

[stitchdup]

32 minutes ago, Andrew McD said:

Is there a trick or technique to aligning parts for pinning?  How do you get a hole located that will line up correctly with the piece that has the pin?

dab the point of your pin in paint then use it t mark the spot for drilling

[peteski]

4 hours ago, Andrew McD said:

Is there a trick or technique to aligning parts for pinning?  How do you get a hole located that will line up correctly with the piece that has the pin?

Yes, there are techniques for that.

For example with side view (door) mirrors I drill a hole for the pin in the mirror's stem, then I insert piece of brass rod (the "marking pin") into the hole until it bottoms out, then using nippers I cut it to just protrude about 0.020" (or about 1/32") from the mirror's stem.  That pin remains not glued. I sometimes take out that piece of the pin and sharpen the end, but sometimes the cutting process leaves a sharp end already.  So when that short pin is in the mirror's stem, I then hold the mirror in its desired mounting place on the door's surface, and I press the sharp pin into the paint. That gives me a mark where to drill. I  then remove the "marking pin" from the mirror stem, and permanently glue in a longer pin. It can be then glued into the hole you drill in the door. If the angle of the hole in the door is at a slightly wrong angle, the pin in the mirror's stem can be bent slightly until desired placement is achieved.  Once everything is lined up, the mirror with its pin can be glued to the door.

If you are worried about messing up the paint while marking and drilling, this process can be done before the bare plastic body is painted. Actually I usually do it this way.

[Andrew McD]

Thanks Petski and stitchdup for your responses regarding pinning.  I hope my question and their responses added to the pre-build info in the thread.......I know it will help my building.

[Rocking Rodney Rat]

On 5/8/2023 at 12:42 PM, Andrew McD said:

Is there a trick or technique to aligning parts for pinning?  How do you get a hole located that will line up correctly with the piece that has the pin?

I sometimes make the hole bigger than the pin so I have a little 'wiggle room'....

As far as pre-building, every part is carefully removed from the sprue, attach points are cleaned up, mold lines removed, light sanding to ensure paint adhesion and yes, lots of mocking up with the above items, blu-tack or white gloo. Final sanding with 800 to 1000 grit paper, a good hot soapy wash, dry and primer all parts, sand primered large parts (body, etc.) more washing, spray color and clear. And then I make sure I get super-glued fingers on a few key painted parts...it's all part of the fun... -RRR

[Sidney Schwartz]

Good stuff here....thanks much, everyone. I'm going to try the tacky glue.

[Chariots of Fire]

Pre-building will work up to a point but as sooner or later during the build, permanent bond is going to be required.  I do a lot of scratch building so I guess pre-building is part of the process I use but I never think of it that way.  Thinking ahead about what will be coming next is a good way to keep things moving in the right direction.  Many times during the building process I have had to make adjustments.  It's just part of the process.  Sometimes what I thought would work actually doesn't so an alternative has to be used.  In the fire service it's called pre-planning, that is, doing all you can before the s.... hits the fan and you have to fly by the seat of your pants!?