DIY Spot Welder Using Two Microwave Power Transformers — a cautious how-to

⚠️ Important disclaimer (please read)

Disclaimer: This DIY involves very high-voltage transformers and wiring and could fatally electrocute you or someone else, start fires, or cause serious injury or property damage. This project is for entertainment/educational purposes only and does not endorse anyone attempting it. Do it at your own risk. If you are not experienced with mains electricity and transformer safety, stop now and buy a commercial spot welder or ask an experienced professional.

What this blog will (and won’t) do

What you’ll get here:

• A conceptual explanation of how to use two microwave power transformers (MOTs) to create a DIY spot welder.

• A general materials and tools list.

• Safety guidance and recommended protective measures.

• Alternatives that are much safer and often cheaper in the long run.

What I will not provide:

• Exact wiring diagrams or step-by-step instructions for modifying MOTs or wiring mains terminals in a way that could cause electrocution.

• Specific measurements, voltages, or instructions to bypass safety features on appliances.

• Anything that would knowingly enable unsafe modification of high-voltage equipment.

The working spot welder:

Starlink Mini DIY Battery Pack!

Take your Starlink Mini anywhere! This compact DIY battery pack keeps your Starlink online off-grid—perfect for RVs, camping, or emergency backup. Reliable, portable, and hassle-free… and best of all, you can build it for a fraction of the cost of commercial options!

On Sale! Flame King Refillable 1LB Empty Propane Cylinder Tank

 AMAZON DEAL FINDER!

Flame King Refillable 1LB Empty Propane Cylinder Tank On sale for $14.50 today, hurry this deals usually don't last long. I got same bottles 8 years ago for about $10 each. Regular price now is about $29/ tank.

You also need Flame King Propane Refill Fitting Adapter Valve for 1LB Camping Refillable Tank Cylinders.

Stand: Flame King Propane Refill Stand for 1LB Camping Refillable Tank Cylinders fits Standard 20Lb Propane Tanks

Refill Kit + 1-lb empty refillable tank: Flame King Refillable 1LB Empty Propane Cylinder Tank - with Refill Kit and CGA600 Connection

Mounting Starlink Mini on NCV3 Sprinter Dashboard

After brainstorming a variety of ways to mount the Starlink Mini on my Sprinter’s dashboard, I had two main goals: keep the dish securely in place during travel and make it easy to remove for repositioning—especially when the dashboard view is blocked by trees or other obstructions.

Finding the Right Spot

The dashboard top center cubby turned out to be the ideal mounting spot. However, it's partially covered by a front-facing plastic trim piece that must be removed to fit the Starlink dish. This piece is secured with screws hidden beneath the L-shaped vent trims, which requires first removing the radio surround to access. Be sure to disassemble the trim pieces in this order for proper removal.

Once cleared, the dish slotted in as if the space were made for it. It sits low and blends seamlessly with the dashboard, giving it a clean, factory-installed look—while also keeping a low profile to deter theft.

For step-by-step trim removal instructions, see this earlier post – click here.

Bathroom Vent Fan Caulk Replacement Turned Full Restoration

What started as a simple task of replacing the aging caulk around my RV's bathroom vent fan quickly turned into a much bigger project. I initially planned to remove the old caulk, reseal the edges, and call it a day. However, upon closer inspection, I discovered that the fan casing had rusted significantly. Rather than replacing the entire fan, I decided to restore and improve it by removing the rust and applying a durable powder-coated finish.

• If you choose to replace the bathroom fan, it is available on Amazon: VENTLINE/DEX VP543 6" 12V Powered Round Vent
• Butyl Tape for sealing fan into roof: Dicor BT-1834-1 Butyl Seal Tape - 1/8" x 3/4" x 30' 
• Polyurethane Sealant: Sika Sikaflex-221 White or Sikaflex 521 White (more UV resistant)