Thunder Tiger Challenger restoration

[XLR8]

For what it's worth, lacquer thinner has always been my go-to all purpose de-greaser and adhesive remover - it cuts just about everything. I've used it to clean G10 many times and it has never caused any harm. It will dissolve styrene however. Be sure to use it in a well ventilated space as the fumes can be rather strong.

[Lowgear]

So far I've tried isopropyl alcohol but didn't have 91% strength. What I had didn't do anything. Next I tried acetone, and it removed 3/4 of the residue stains with a lot of scrubbing! I might try lacquer thinner next to see if it will get rid of the rest. They're barely noticeable now, and I could always leave it. I'm sure if I waxed the pieces it would completely hide the spots but I'm curious to see if they can be removed completely, and not just hidden.

[jwscab]

awesome!!! laquer thinner is also a great solvent to try, i usually don't keep it around so that's why i don't use it, but it has a nice blend of hydrocarbons that will dissolve tons of stuff.

[Coelacanth]

WD-40 is my go-to for general grease/dirt removal, sticker adhesive removal and cleaning. When parts are done being cleaned with WD-40, I wash off the WD-40 residue with hot water & Dawn dish soap, make sure they're dry, and reassemble.

I use rubbing alcohol (91%) for minor cleaning of smooth, non-porous surfaces like Lexan, but not much else. It's not stong enough for fast degreasing. WD-40 and a toothbrush or paintbrush, it's a bit of elbow-grease brushing small parts with lots of nooks and crannies, but it works almost immediately.

[Lowgear]

I wasn't overly impressed with the Oil Eater product I tried. It's one of those products that's supposed to be so great, and several places online recommended it including R/C ones but it was just 'meh' to me. I used it full strength too and it took an inordinate amount of effort on my part to get all the grease and grime off the parts. I even let some stuff sit submerged in it for awhile thinking that was the problem but It didn't make too much of a difference. What should have taken an hour or two each session took five. I liked the fact that it's non-corrosive, non-toxic, and biodegradable. As clean as I try to be while using an amount of chemicals like that, I end up getting them all over myself and immediate area. Once I was done I dumped the foil pans of the stuff outside over some gravel which was nice.

This was not the right project to have been started this time of year though! Most of it requires working outside, and that's not an option as everything is encased in snow and ice. I'm doing what I can in the garage but things like stripping and painting the roll cage will have to wait until late April or early May. I didn't realize this project was going to be a can of worms until I got into it or I would have waited until late spring/summer. Isn't that how it normally goes though?

Cleaning wise I still have to do the rear shocks, tires/wheels, radio box, front assembly, fuel tank, and engine.
Sanding wise I have to do the frame rails, cross support bars, and rear bumper side plates. I'm just trying to take the marks out, and make them an even matte finish.
I'll also be replacing the bushings in the trans with bearings if I can. I already got new bearings for the rear trailing arms. Stock, the front wheels ride on nothing believe it or not but there's a recess on the backside. I took measurements with my calipers, and I think a bushing will fit in there.
Last but not least I'm going to try gun bluing some of the steel pieces that have the finishes worn off like the drive components for example.

I have a feeling this will take most of winter to finish (besides painting) but that's okay. I enjoy working on it here and there when I have the time, and that's what it's about.

[Lowgear]

Wow, I hadn't realized that it's been over 3 months since the last update! Anyway, I've been working on this whenever I get the spare time which isn't as often as I'd like. When I do work on it though I spend hours. I'm still going through the process of refinishing all the parts. The problem is I've become obsessive compulsive to an unhealthy degree with how things turn out when ultimately it's still a used buggy overall.

With all the parts I wanted to have a uniform matte finish on, I figured I'd have to sand them to get the result. Then one day while looking at the frame rails I realized they had way too many marks for just sanding alone. It then dawned on me that maybe media blasting them on a low PSI might work better. I knew I'd still have to do a final finish on them afterwards somehow but figured it would produce a much better result. I tested it out an a junk Rowdy Baja frame rail I have, and it worked perfectly but looked horribly 'sand blasted' as expected. I don't know why but I took a piece of 0000 steel wool and buffed the blasted aluminum, and it came out exactly like I wanted! So I ended up doing a bunch of pieces, and here's the result...

Rear bumper and cage mount brackets. These were originally chrome that made them look cheap. They were also both covered in stains. The top is blasted, the bottom is after buffing with the steel wool:

Side cage to frame mounts. These had ugly marks on them possibly from the factory, and were also stained. Unfortunately one of them has a split from the stress of roll overs. Not that big of a deal but I'd like to replace it in the future. Blasted on the right, final finished on the left:

Transmission housing cover. This was in bad shape. It was bent, scratched, tarnished, and had CA glue on it. I used acetone to remove the glue, a body hammer and dolly to straighten it out, and then blasted it to remove the rest. I don't have an individual pic of the cover after final finish but you can see it in the group shot below:

Finished group shot:

Four days ago I had some more time to work on this so I media blasted the remaining parts that needed it. Those were the cross braces, skid plate, and frame rails. It took me 4 hours to do as the blasting cabinet is a piece of junk, and the media is worn out and only half remaining. Plus at the very end the trigger jammed and I had to take the gun apart to fix it. The parts came out perfect though so I was happy in that regard. Then two nights ago I spent another 3 hours sitting on the basement floor buffing those parts with the steel wool. The cross braces and skid plate came out great but after doing the frame rails I realized they both have different textures! One is smooth and looks how it's supposed to but the other rail has a bumpy texture. A grain in the aluminum is the best way I can describe it. It came from the factory this way, and between the original raw aluminum finish, and how marked up and grimy they were, I never noticed it until now. It's upsetting as after finishing both rails, they're two different shades from one another as a result. Then to add insult to injury, while I was using a neodymium magnet to remove any remaining steel wool shavings from my clothing, I got too close to the skid plate which snapped onto the magnet scratching the finish I just finished doing! I guess things like that happen when you're tired. So now I have to media blast the scratched part and buff it out again. Between that and the frame rails, it really took the wind out of my sails.


Cross braces and skid plate after blasting. The skid plate was one of the worst parts cosmetically:

Cross braces blasted versus finished:

Frame rail problem. You can clearly see what the issue is. they're both finished. The one on top is how both are supposed to look. A nice uniform silver finish. The bottom one has the texture, and it encompasses all four sides. That isn't the reflection from the paper towel:

This project has become a can of worms that's been a monkey on my back for nearly 5 months now but I can't quit as I've already spent countless hours and hundreds of dollars so far on it. I know I'll feel better once I can start putting it back together again but that won't be for a seemingly long time.

[coxbros1]

1st off great work....
2nd plenty of time with the quaratine
3rd we are all bored and need to see it finished!

[Coelacanth]

Looks like your frame rails were cast differently. I've also seen aluminum surfaces with that texture. At any rate, you should be able to get the weird textured one to match the media-blasted one with wet-sanding. Looks like you'd need to start with 200 or 400 grit until you get a uniform finish, then work your way up until you match the other rail's finish. It looks like 600 to 800 grit satin finish to me. Or you could go the whole 9 yards and polish them both right up to 1000 or 1500 grit, and get a polished aluminum/near chrome-like finish.

[Lowgear]

1st off great work....
2nd plenty of time with the quaratine
3rd we are all bored and need to see it finished!

Thanks I also have the restoration of the trans nearly completed that I'll be posting about. It just needs to be reassembled and a new gasket made for the housing cover. I'm in the process of rebuilding the engine as well.

Looks like your frame rails were cast differently. I've also seen aluminum surfaces with that texture. At any rate, you should be able to get the weird textured one to match the media-blasted one with wet-sanding. Looks like you'd need to start with 200 or 400 grit until you get a uniform finish, then work your way up until you match the other rail's finish. It looks like 600 to 800 grit satin finish to me. Or you could go the whole 9 yards and polish them both right up to 1000 or 1500 grit, and get a polished aluminum/near chrome-like finish.

The frame rail in the background has not only been media blasted, its been buffed with the steel wool as well to the finished surface. Both frame rails have been, but you can see how the one with the poor casting turned out a lot differently. If I attempt to try and fix it, I'd do what you suggested with the 200-400 grit wet sand until I got it down to a uniform surface. I would then media blast and steel wool buff it again. I don't want to go the polishing route with this build as I always do that. It's like I'm a one-trick pony when it comes to aluminum, so for the first time I'm trying something different. Either way, I'm just afraid that sanding it down until I hit a uniform surface will take too much material off. Especially since I have to do all four sides. It's even worse than the picture shows. I tried sanding a little in an area that will be hidden, and some pits go pretty deep. I suppose it won't hurt to try fixing it as I can't bring myself to use the rail in its current condition. I just don't want to wreck it, and then be screwed. I'd have to wait for a parts buggy to come up for sale for a replacement rail if that happens. I'll have to mull it over a bit before proceeding.

[Coelacanth]

For interest's sake, have you measured the thickness of each frame rail with a caliper? If you're lucky, the weird-textured one might be slightly thicker due to the raised textures, and by sanding down the textured surface, you'd actually be getting both rails to be more or less the same thickness.

[jwscab]

the frame rails are not cast, they are extruded square stock. I've seen this in the past, it's the alloy, and how it was pushed through the die, sometimes you get this type of marbling on the finish.

You're best bet is to sand both down and then bead blast, and you should get pretty much the same finish at that point.

[Lowgear]

For interest's sake, have you measured the thickness of each frame rail with a caliper? If you're lucky, the weird-textured one might be slightly thicker due to the raised textures, and by sanding down the textured surface, you'd actually be getting both rails to be more or less the same thickness.

That's a good idea I hadn't thought of! Unfortunately I'm not a lucky person. I just measured and the bad frame rail is slightly smaller. Maybe that's why it ended up the way it did. I measured from several different spots and it averages out to 11.60mm. The good frame rail averages out to 11.90mm.

the frame rails are not cast, they are extruded square stock. I've seen this in the past, it's the alloy, and how it was pushed through the die, sometimes you get this type of marbling on the finish.

You're best bet is to sand both down and then bead blast, and you should get pretty much the same finish at that point.

Marbling is a really accurate way to describe the finish. It appears as if it's going to come down to sanding both so that they match if I want to fix these ones. I'm definitely not enthusiastic with the amount of effort it's going to take as I'll have to do both all over again on top of the sanding. This is one of those times a mill would have come in really handy. I'm going to hold off on it for now while I complete other parts of the restoration. Maybe in that time something will come up on eBay. There's a parts buggy on there right not but it's in way too bad of shape. I was also thinking of buying the complete one that's on there with the wrecked cage, and swapping its frame rails with my wonky ones, and then reselling it. That's going a little overboard though.

[Dadio]

I know its not what you want but you could paint the frame rails ,two coats of paint would probably cover the marbling .

[Lowgear]

That would technically work but would be an I've completely given up on life last resort.

[jwscab]

if you hold them in a vise with some cushion on the jaws, you should very easily be able to use a sharp file add draw file the profile to a nice uniform finish. it' won't take long at all. look up the draw file technique. essentially, you hold the file perpendicular to the orientation of the object and pull it towards you with both hands. it leaves a really nice finish and you have really good control.