How Cold is Too Cold to Spray Rustoleum Oil-Based Paint?

I wasn’t sure if there’s a lower temperature limit to spraying Rustoleum, but I took a chance. I needed to paint a steel cabinet.

As night was falling, at a temperature of around 34°F, I sprayed Rustoleum Oil-Based (alkyd) enamel, thinned with acetone, using my trusty Harbor Freight HVLP gun. After sitting for a couple of hours, I brought the cabinet into the attached — but poorly insulated — garage. The overnight low was supposedly 14°F, but the garage probably averaged around 30°F for most of the night.

At around 16 hours after spraying, I returned to the garage and found the paint completely dry to the touch. I could make a fingernail mark with enough pressure, but I was able to reassemble everything without marring the finish.

This isn’t to say you’ll get optimal results, but the paint sprayed, covered, and dried as expected. I’ll update this post if I see any signs that adhesion or strength was compromised.

Airgas vs Industrial Welding Supply

I bought a cheap, Chinese MIG welder and needed some C25 gas. I wanted a cylinder in the 80 – 150 cubic foot range. I checked Airgas first, since they’re less than a mile away. The next day, I stopped at Industrial Welding Supply and was shocked at the price difference:

Airgas Industrial welding supply
Monthly Rental $35 $5
Annual Lease $126 + Hazmat fee $52, no Hazmat fee

Note: If I remember correctly, the prices for Airgas were for a 125 cubic foot cylinder, and the Industrial Welding Supply prices were for a 130 or 135 cubit foot cylinder.

So, renting a bottle for one year at Airgas would cost a whopping $420 per year, plus fill costs! By comparison, renting at Industrial Welding Supply will be only $60 per year, plus fill costs ($38 to fill with C25). Obviously, I’m going with Industrial Welding Supply. I went with a monthly rental because it only costs an extra $8 per year, and doesn’t require opening a full-blown account. The rental just requires a basic credit check (SSN, drivers license, address, etc.) that took five minutes. The $5 monthly bill is sent out as an actual paper bill, which is a mild annoyance, but somewhat adorably quaint.

Incidentally, on the subject of leases, I was told at Airgas that if I returned a leased bottle after a partial year (e.g. three months), I wouldn’t get any money back. Industrial Welding Supply told me that they pro-rate partial years.

Another minor detail: Airgas mentioned that they only do bottle exchanges (i.e. owner bottles, not rented or leased) up to 80 cu ft, with the odd exception of 150 cu ft. So, they’ll sell you an 80 cu ft bottle, and they’ll sell you a 150 cu ft bottle, but they won’t sell you a 125 cu ft or a 300 cu ft. It’s a weird exception, and may vary by location.

Spraying Gelcoat Cheaply

Spray Gun Options

I’m reproducing a part in carbon fiber, which requires me to make a mold of the existing part.  For accuracy and durability of the mold, it’s best if the first layer is sprayed gel coat. Gel coat is normally sprayed with a “cup gun” like the E.S. G100 Cup Gun.  At around $175, it’s more than I’d like to spend for my relatively small project, though I’m sure it’s great for professional use.

Cup gun used for gelcoat
E.S. G100 Cup Gun, a professional tool for spraying gel coat

Since I already have a couple of the purple Harbor Freight HVLP guns, I wondered if gel coat could be shot with an HVLP gun.  My Harbor Freight guns have 1.3 and 1.4mm tips, which are great for shooting paint and primer, but gel coat is extremely thick compared to even a high-build primer.  This spray gun website recommends a 2.0mm or larger tip for playing gel coat.  It recommends 2.5-3.0mm for “full coverage on boats”, and claims to have guns up to 7.5mm for large molds!

Unfortunately, Harbor Freight doesn’t sell additional tip sizes.  It may be possible to find out what gun Harbor Freight copied, go to a local auto body supplier, and look for replacement tips there, but that will almost certainly expensive. Most likely, it’s cheapest just to find a complete, Chinese-made HVLP gun with a tip in the 2.0 – 3.0mm range.

This boating forum discussion recommends the Vaper HVLP spray gun with 2.3mm tip for $39.99 at NorthernTool.  Shipping is $7.49, and it’s currently backordered, so I kept looking for other options.

Northern Tools Vaper HVLP gun
Vaper HVLP gun with 2.3mm tip, from Northern Tool for $39.99 + shipping

I then found this listing for a 2.5mm HVLP gun (eBay seller yescomusa) for $37.90, with free shipping. This appears to be the cheapest option, and it doesn’t require me to swap out any parts when I want to go from shooting paint to shooting gel coat.

2.5mm HVLP Spray Gun from eBay seller yescomusa
Complete HVLP gun on eBay with 2.5mm tip, for $37.99 shipped

Another option might be the texture spray gun from Harbor Freight, intended for shooting popcorn texture on ceilings. It’s $26.99, and comes with 4mm, 6mm, and 8mm tips. This forum post says it works well.

HarborFreight Texture Spray Gun
Harbor Freight Texture Spray Gun, for wall and ceiling texture

Gel Coat Options

TAP Plastics has white or neutral gel coat, without hardener, priced at one pint for $17.25 or one gallon for $89.50.

TAP Plastics Gel Coat
TAP Plastics Gel Coat, $17.25 per pint, plus catalyst and shipping

A cheaper option is eBay seller promboats, who sells a quart of white gel coat, with hardener, for $25.50 shipped.

White Gel Coat from eBay
White Gel Coat from eBay, $25.50 per quart, shipped

Is Reputable?

I was looking for an EBC rear rotor for an RD04 Africa Twin, a bike which was never imported into the USA. No online shops in the country sold them, except, seemingly, one: TheRideStop.

I put the item in my shopping cart and was shocked to see a shipping price of several hundred dollars. This alerted me that the site might be a scam.

A few days later, I happened to look at the site again. This time, adding an item resulted in more normal fees. Something still seemed fishy, so I did a search on the name. I found only this:

DON’T use the Ride Stop! I was just ripped off by them and am having my CC co. charge back the money.

Also, this thread mentions:

Unlike the folks at where I ordered some W&M bags. It’s been a week now and I still don’t have a tracking number, let alone my bags!

To boot they stated (after I complained about the lack of shipping confirmation) “you paid less than anywhere else so this is the trade-off I guess.” Go figger.

Seating Tire Beads

I was putting new tires on my 1977 CB750. The rear tire went on and the bead set without too much difficulty, but the front tire was proving more troublesome.

Previously, I had been running the Comstar wheels without tubes — something not officially endorsed until, I believe 1982 — and had used a bit of tire sealant to help the bead seat. Over the years, this liquid sealant had hardened into a concrete-like state, and despite my best efforts I believe a bit of it was impeding the process of seating the tire bead.

I tried all the usual steps to get the bead to seat. I lightly inflated the tire, then methodically bounced the wheel against the ground. I wrapped a tie-down strap around the circumference of the tire, which deforms the tire and forces the bead outward. I even tried inflating the tire as high as 80psi, all to no avail.

Incidentally, do not inflate tires to such high pressures, people really have been badly injured doing this.

After more than an hour, I gave up and left the tire overnight with around 50psi in it. The next day, I was happy to see that the bead had seated itself.

Sometimes the solution is simply to have patience.

1995 Grand Cherokee Track Bar Replacement

In an effort to eliminate a front-end clunk when steering, I installed a new Moog track bar. The toughest part of the process is removing the ball joint from the frame mount. The ball joint is pressed into a tapered hole in the bracket, and this bracket makes it impossible to use a pitman arm puller.

Instead, a pickle fork (or “ball joint separator”) must be used. I found that the only way to get sufficient impact was to use wire cutters and snip away the rubber boot. Then, by either removing the driver’s side wheel or turning it to the left, it’s possible to get the pickle fork at a good angle on the joint. This gave me enough room to get the four-pound sledge hammer up to speed, and the joint popped free after a couple of whacks.

When installing or removing the trackbar, it’s important to raise the body of the vehicle, then adjust the relative height of the axle using a jack. This allows you to align the axle-side mount correctly, avoiding unnecessary interference and friction. Without this step, it will be easy to snap the bolt.

Cars, motorcycles, maintenance and fabrication