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Metric Concave Cup Expansion (Freeze) Plugs


QualCast Expansion Plugs are produced from the highest quality steel in a wide variety of cup designs. For marine, performance, or heavy-duty applications we recommend brass or stainless-steel materials. We carry standard cup, shallow cup, and concave cup in all three materials, as well as in metric sizes.

Find individual specifications in the listings below.

NOTE: QualCast products ship directly from the QualCast warehouse to your door. Please allow additional time for processing and delivery.

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Order No. Description Price Quantity
QC9618MMCC 18mm Hole Dia. | 18mm OD | 96-18MMCC $0.37
QC9621MMCC 21mm Hole Dia. | 21mm OD | 96-21MMCC $0.40
QC9624MMCC 24mm Hole Dia. | 24mm OD | 96-24MMCC $0.40
QC9640MMCC 40mm Hole Dia. | 40mm OD | 96-40MMCC $0.82
QC9642MMCC 42mm Hole Dia. | 42mm OD | 96-42MMCC $0.82
QC9645MMCC 45mm Hole Dia. | 45mm OD | 96-45MMCC $0.85
QC9652MMCC 52mm Hole Dia. | 52mm OD | 96-52MMCC $0.98

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To return an item:
1. Write a brief note describing the reason for the return. Please be sure to include your name or company name or account number.

2. Return the item freight prepaid within 60 days from the invoice date. For best results, please ship return merchandise by UPS or Federal Express. Please keep your receipt because it may be necessary to track the package if it is lost in transit.

3. A 10% restocking fee applies on all returns unless the problem was the fault of Goodson. If so, the restocking charge is waived and shipping costs are reimbursed. Credits will be made to the account originally billed.

Send the completed Product Return Form along with the product to:

Goodson Shop Supplies
156 Galewski Drive
Winona, MN 55987

Read our complete return policy.


Goodson strives to ship orders the same day they are recieved. In fact, we track this on a daily basis and we are currently shipping 99.97% of orders on the same day.

We use most major carriers including FedEx, UPS, USPS and regional carrier, SpeeDee.

For more information, check out our Shipping & Delievery page.

International Sales

Goodson ships F.O.B. Winona, Minnesota, USA to most countries around the world. To find a distributor near you visit our Distributor Listing.

If there is not a distributor in your area, you can contact Goodson by phone (1-507-452-1830) or order online. Please note some items (such as Sunnen) are not available for shipping outside of the United States & Canada. If you have these items in your shopping cart, your order cannot be processed. You must remove those items from the cart to continue.

Proposition 65 Information

"Proposition 65 requires businesses to provide warnings to Californians about significant exposures to chemicals that cause cancer, birth defects or other reproductive harm." -  

So, what does this mean for Goodson customers? It means that many of common products used in manufacturing contain products known to the state of California to cause cancer and/or reproductive harm. Components such as stainless steel, galvanized wire, brass, bronze, etc. can be found in the Prop 65 list and require us to provide the warning. 

You can find a complete list at the Proposition 65 website.

Proposition 65 WarningWARNING: Cancer and Reproductive Harm -